Files
windmill/backend/generate_mcp_endpoints_tools/generate_mcp_tools.py
92a454b7a8 fix: split the MCP script tools into createScript and updateScript (#10783)
* fix: let the MCP createScript tool deploy without a parent hash

The tool advertised creating a new script with `parent_hash` left unset, but
`parent_hash` was one of its declared arguments — and a client that requires
every declared argument to be filled has no way to leave it unset. The values
such a caller invents (`""`, `"0"`, a zero hash) are all rejected by
`/scripts/create`, so no script was ever created.

`parent_hash` is now gone from the tool, and the MCP layer sends `auto_parent`
in its place: the server resolves the lineage from the path, creating the script
when the path is free and deploying a new version of it when it is not. That is
what the tool already claimed to do, and it no longer asks the caller to track a
hash to do it.

`x-mcp-tool-fixed-fields` is the general mechanism behind this — body fields the
MCP layer fills in itself, absent from the tool schema. A null argument is also
dropped from the assembled body now, for the same reason the placeholder hashes
were a problem: it is how a caller with no value to give says so, and the API
rejects it rather than falling back to the field's default.

Fixes GIT-973

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix: hash a script version once auto_parent has resolved its parent

`create_script` hashed the incoming script before the `auto_parent` block filled
in `parent_hash`, and the version hash covers that field. A deploy that let the
server resolve the parent was therefore hashed as if the path had no history, so
redeploying content the path had held before collided with that archived version
and returned "A script with same hash ... already exists!" instead of becoming a
new version of the lineage. Reverting a script to an earlier state was impossible
for any caller relying on auto_parent alone, which is now every MCP caller.

The hash and the duplicate-hash check move below the resolution, so an
auto_parent deploy hashes the lineage it will actually be attached to. Callers
passing an explicit `parent_hash` are unaffected: the resolution block leaves
their `ns` untouched, so they hash exactly as before.

The CLI masked this by sending `parent_hash` and `auto_parent` together, using
auto_parent only as a stale-hash fallback.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs: state the constraint that pins the script hash site

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix: reject a fixed-fields spec the MCP layer would not honour

`validate_fixed_fields` ran only for an operation that declares a request body,
and passed any body whose properties it could not see. Two shapes reached the
generated tool with fixed fields that are dropped at call time: an operation with
no `requestBody`, where the body builder returns before reading them, and a
pass-through body, which carries the runnable's own arguments and never receives
a key of ours. Both are now generation-time errors, so the only specs that get
the extension are the ones where it means something.

Also name the folder-derived `on_behalf_of` alongside `parent_hash` at the hash
site: both are written to `ns` before it, and a reader who knows about only one
could reintroduce the early hash.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix: keep fixed fields internal and catch a misspelled one

`EndpointTool` is what `list_tools` publishes as the tool catalogue, so deriving
`body_fixed_fields` into it put a field in the caller's view that is by definition
not the caller's to set, and that the OpenAPI schema does not declare. It is no
longer serialized.

The generator also only checked a fixed key against the exposed subset of the body
properties, which cannot tell a field deliberately left out of
`x-mcp-tool-include-fields` from a misspelling of one. A key the API does not
declare is now a generation-time error rather than one serde discards in silence,
and the extension must be a non-empty mapping — an empty list previously slipped
through the type check on its way to being ignored.

Narrow the hash-site comment to the ordering it actually constrains.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* feat: split the MCP script tools into createScript and updateScript

Scripts were the only entity in the MCP surface without the create/update pair
every other one has, because the REST API has no update route for them: a script
is immutably versioned, so `POST /scripts/create` is also its update, and one
tool had to infer which the caller meant from the state of the path.

That inference is what GIT-973 is. `parent_hash` told the two apart, and an MCP
client that requires every declared argument to be filled has no way to leave it
unset, so no script could be created: `""` is a 422, `"0"` is a 422, and
`"0000000000000000"` is a 400.

Naming the intent removes the field instead of the guard. `createScript` means
the path should be free and keeps refusing an occupied one; `updateScript` names
the version it supersedes in its URL, so the body carries no hash either. Picking
the wrong one now fails loudly rather than succeeding on the wrong script.

- New `POST /w/{workspace}/scripts/update/{path}`, deploying a new version of
  the script the URL names. Its body `path` is the destination, defaulting to the
  URL's, so setting a different one moves the script and keeps its history —
  which no MCP client could ask for while `createScript` was the only tool.
- New `x-mcp-tool-optional-fields`, dropping a body field from the tool's
  `required` where the handler defaults it. `updateScript` uses it for that
  destination path: required, an agent has to restate the path on every edit, and
  a value that drifts from the URL's silently moves the script.
- `assemble_request_body` drops null-valued arguments, matching what the
  pass-through branch already did. A client that must fill in every argument says
  "no value" with `null`, and the API rejects that for a bare `String` field
  rather than falling back to its default.

Fixes GIT-973

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* fix: confine updateScript to the token's script paths

`endpoint_path_policy` is what applies an `mcp:scripts:<pattern>` token's path
patterns to an endpoint tool, and a tool it does not name is not confined at all.
`updateScript` was not named, so a path-scoped token could deploy over, and move,
any script in the workspace: the proxy mints a bare `scripts:write` for a caller
whose only scopes are `mcp:`-prefixed, and nothing downstream held a pattern.

The destination path has to bind only when supplied — omitting it is how a caller
updates in place — so `PathArgs` grows `optional_fields`, checked when present and
never required. Empty reads as absent, matching the handler, which now takes an
empty body `path` for "leave it where it is" rather than moving the script to the
empty path: a caller obliged to fill in every field sends `""` as readily as null.

That shape also fixes `updateFlow`, whose entry named `path__path` for the URL
argument. The generator gives the URL path the plain name, so the lookup never
matched and every confined call failed closed on a missing argument.

Both sides now have a drift guard: a script/flow tool the URL addresses by path
must have a policy. The backend one lives in windmill-api, where the generated
catalogue is, since the policy is in windmill-mcp and neither crate sees both.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* fix: address the review round on the script tool split

Four findings, three of them one bug: a destination path the caller left empty.

`update_script` read it as "leave it where it is", the confinement check skipped
it on the strength of that, and `update_flow` did neither — it takes the empty
string literally and moves the flow there, so the skipped check was the only
thing standing in front of that move. A database constraint refuses the empty
path, so nothing was reachable through it, but the confinement was relying on a
property of one handler that its sibling did not have.

The MCP layer now strips an empty optional destination from the arguments, so no
handler receives one and there is nothing left for the check to skip. Neither
tool depends on the other's reading of it any more.

`update_script` also resolved the head before opening the deploying transaction.
A version landing in between is caught — it leaves a child behind, and the
linear-lineage check refuses that — but an archive leaves none, and the hash of
an archived version still exists, so the deploy would have chained onto it and
revived the script the archive had just retired. The resolution moves into the
transaction.

The scope check on the URL path moves ahead of that resolution, so a path outside
the token's scope answers the same whether or not a script is there, rather than
telling the two apart through 404 against 403.

`x-mcp-tool-optional-fields` goes: the generator already strips a body field that
collides with a same-named path parameter from `required`, so the extension
regenerated byte-for-byte identical output. The test that pinned the destination
as optional stays — it pins the behavior, which is now the collision handling's.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* fix: lock the head an updateScript supersedes

Moving the resolution into the deploying transaction narrowed the archive race
without closing it. The plain SELECT took no row lock, so an archive could still
land between it and the parent-existence check below, which finds the parent by
hash and never looks at `archived` — the deploy then chained onto the archived
version and inserted a live child, reviving the script the archive had retired.

`FOR UPDATE` on the resolution is what makes the row the head rather than a head
it once was: the archive either waits for the deploy, or wins and leaves the row
failing the `archived` qualifier on re-check, so no version resolves at all.

The regression test stages that interleaving rather than approximating it. It
holds the head row from a second connection so the deploy parks on it, waits for
a backend to actually be blocked before archiving — without that wait the request
loses to a local UPDATE and never reaches its resolution, which is the sequential
case the neighbouring test already covers — then asserts the update is refused.
It returns 201 and revives the script with the lock removed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* fix: have the MCP layer name the path an update keeps

The tool lets a caller omit the destination, and the endpoint was absorbing that
by accepting a body without a `path` and defaulting it from the URL. The OpenAPI
schema says `path` is required, so the two disagreed and a generated REST client
could not follow the contract the description promised.

The MCP layer fills the destination in instead, from the path the item is already
at, since that is what omitting it means. The endpoint then always receives a body
naming its own path and matches its schema, `update_script` takes a `NewScript`
rather than picking a JSON object apart to inject a default, and the empty string
stops being a value any handler has to interpret — `update_flow` reads one as the
empty path, which is why it was stripped a commit ago.

The alternative, an `EditScript` schema differing from `NewScript` only in whether
`path` is required, was measured and rejected: openapi-ts drops the `required` of
an `allOf` branch, so `NewScript` came out with every field optional and broke 15
frontend types. Loosening a schema every API consumer shares, to make one field
optional on one route, is the worse trade.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* fix: tell a superseded update apart from a missing script

Locking the head made the loser of two concurrent deploys answer 404 "Script not
found" for a path the caller can see holds a script: its lock re-check finds the
row archived and filtered, and nothing looked further. It now looks — a live
version at the path means this deploy lost to one that superseded the version it
set out to supersede, which is a conflict to retry, not a script to go find.

The regression test stages that interleaving the way the archive one does, with
the winner leaving a live head behind rather than an archived path. It answers
404 with the branch removed.

The rationale for the lock also sat in two places; it stays at the query, which
is where dropping it would do the damage.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: drop the path default update_script no longer applies

The handler stopped defaulting the body's path when the MCP layer took the job
over; its doc comment still described the old contract.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: sync the deref YAML with the update route's path contract

The dereferenced bundle rewraps prose at its own width, so the edit that updated
the canonical spec and the JSON bundle matched nothing here and left the served
YAML still offering a default the endpoint no longer applies.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: stop the script tools describing a parent_hash they cannot take

`description` is read by two audiences: it documents the route, and it opens the
MCP tool's text. Written for the first, it told an agent that createScript
"does it too when given that version's `parent_hash`" — a field neither tool
exposes, and inviting exactly the call this branch exists to make impossible.
updateScript's told the agent to repeat the URL's path while its own instructions
say to omit it; both work, since the MCP layer fills it in, but only one of them
can be the advice.

Both now describe what the operation does and leave the mechanics to the text
that belongs to each caller: the request body's own description for REST, the
tool instructions for an agent.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: give the create route's two audiences their own description

Removing the `parent_hash` sentence took a true fact out of the REST
documentation: the create route does still deploy a new version, and still
rename, when the body names the version it supersedes. Nothing replaced the
explanation, and the field carried no description of its own.

`description` cannot serve both readers — it documents an endpoint whose schema
has `parent_hash`, and it opens a tool whose filtered schema deliberately does
not. `x-mcp-tool-description` stands in for it on the tool, the way
`x-mcp-tool-name` already does for the name, so the route keeps its full
contract and the agent is not told to send a field it has no way to send.

What `parent_hash` does now sits on the field, where a REST caller looks for it
and where `x-mcp-tool-include-fields` drops it before an agent sees it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: tell an agent a new version is not runnable the instant it deploys

A deploy returns before its lockfile exists, so a script run straight after one
can still execute the previous version.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: say why a new version is not runnable the instant it deploys

Its lock is generated asynchronously, so a script run straight after a deploy
can still execute the previous version. On both script tools: a freshly created
script is no more immediately runnable than a freshly updated one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

* docs: bound the wait after a deploy instead of naming a signal for it

`getScriptByPath` reports the new hash the instant the version exists, while its
lock is still null, so the previous version is what a run by path executes. There
is no signal that fixes this: the deploy evicts DEPLOYED_SCRIPT_HASH_CACHE, but
anything resolving the path before the lock lands re-populates it with the old
hash, and the lock landing evicts nothing. Waiting for a non-null lock is
necessary and not sufficient, so pointing at one would have been a second wrong
answer.

Measured: a run right after the lock lands still gets the previous version, and
the same run 65s later gets the new one, which is the cache's 60s TTL.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CEWFHpmTBauDBi93MnsT7s

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Ruben Fiszel <ruben@windmill.dev>
2026-08-21 10:39:46 +02:00

671 lines
28 KiB
Python

#!/usr/bin/env python3
"""
Script to parse the OpenAPI YAML file and generate Rust and TypeScript code with MCP tools.
Searches for endpoints tagged with 'x-mcp-tool: true' and creates:
- Rust code: A const array in backend/windmill-api/src/mcp/tools/auto_generated_endpoints.rs
- TypeScript code: An exported array in frontend/src/lib/mcpEndpointTools.ts
"""
import json
import sys
from pathlib import Path
from typing import Dict, List, Any, Optional
IMPORTS = """
use std::borrow::Cow;
use windmill_mcp::server::EndpointTool;
"""
def load_openapi_spec(file_path: str) -> Dict[str, Any]:
"""Load and parse the OpenAPI YAML specification."""
try:
import yaml
with open(file_path, 'r', encoding='utf-8') as f:
return yaml.safe_load(f)
except ImportError:
print("PyYAML not found. Please install it with: pip install PyYAML", file=sys.stderr)
sys.exit(1)
except Exception as e:
print(f"Error loading OpenAPI spec: {e}", file=sys.stderr)
sys.exit(1)
def flatten_allof_schema(schema: Dict[str, Any]) -> Dict[str, Any]:
"""Flatten an allOf schema into a single object schema by merging all properties."""
if 'allOf' not in schema:
return schema
merged = {"type": "object", "properties": {}, "required": []}
def collect_from(s: Dict[str, Any]):
if 'allOf' in s:
for item in s['allOf']:
if isinstance(item, dict):
collect_from(item)
if 'properties' in s:
merged['properties'].update(s['properties'])
if 'required' in s and isinstance(s['required'], list):
merged['required'].extend(s['required'])
if 'description' in s and 'description' not in merged:
merged['description'] = s['description']
collect_from(schema)
# Preserve additional top-level keys from the original schema
preserved_keys = {'additionalProperties', 'title', 'nullable', 'default', 'example'}
for key in preserved_keys:
if key in schema and key not in merged:
merged[key] = schema[key]
if not merged['required']:
del merged['required']
return merged
def extract_separate_schemas(parameters: List[Dict[str, Any]], request_body: Optional[Dict[str, Any]], spec: Dict[str, Any], required_fields: Optional[List[str]] = None, base_path: str = "", include_fields: Optional[List[str]] = None, opaque_fields: Optional[List[str]] = None, include_query_params: Optional[List[str]] = None) -> tuple:
"""Extract separate schemas for path parameters, query parameters, and request body."""
path_params_schema = {
"type": "object",
"properties": {},
"required": []
}
query_params_schema = {
"type": "object",
"properties": {},
"required": []
}
body_schema = None
# Process parameters
for param in parameters:
# Resolve $ref if present
if '$ref' in param:
param = resolve_schema_refs(param, spec, base_path)
param_name = param.get('name', '')
param_schema = param.get('schema', {'type': 'string'})
param_required = param.get('required', False)
param_description = param.get('description', '')
param_in = param.get('in', 'query')
# Resolve any refs in the parameter schema
param_schema = resolve_schema_refs(param_schema, spec, base_path)
# Add description if available
if param_description:
param_schema = dict(param_schema)
param_schema['description'] = param_description
# Route to appropriate schema based on parameter location
if param_in == 'path':
# Skip 'workspace' path parameter as it's automatically provided by the MCP context
if param_name != 'workspace':
path_params_schema['properties'][param_name] = param_schema
if param_required:
path_params_schema['required'].append(param_name)
elif param_in == 'query' and (include_query_params is None or param_name in include_query_params):
query_params_schema['properties'][param_name] = param_schema
if param_required:
query_params_schema['required'].append(param_name)
# Process request body if present
if request_body:
body_schema = extract_request_body_schema(request_body, spec, base_path)
# Flatten allOf schemas into a single object schema for filtering
if body_schema and (include_fields is not None or opaque_fields):
body_schema = flatten_allof_schema(body_schema)
# Apply include_fields filter: only keep listed top-level properties
if body_schema and include_fields is not None and 'properties' in body_schema:
body_schema['properties'] = {
k: v for k, v in body_schema['properties'].items()
if k in include_fields
}
if 'required' in body_schema:
body_schema['required'] = [
r for r in body_schema['required'] if r in include_fields
]
# Apply opaque_fields: simplify listed properties to {"type": "object"}
if body_schema and opaque_fields and 'properties' in body_schema:
for field in opaque_fields:
if field in body_schema['properties']:
body_schema['properties'][field] = {"type": "object"}
# If we have required fields specified and a body schema, update the required array
if body_schema and required_fields:
if 'required' not in body_schema:
body_schema['required'] = []
# Add each required field if it exists in the schema properties
for field in required_fields:
if 'properties' in body_schema and field in body_schema['properties']:
if field not in body_schema['required']:
body_schema['required'].append(field)
else:
# Log warning when a required field is missing from schema properties
print(f"Warning: Required field '{field}' not found in body schema properties", file=sys.stderr)
# Marks a body the MCP layer must refuse to leave empty (see non_empty_body_fields
# in windmill-mcp). A pass-through body (no declared properties, e.g.
# runScriptByPath) is excluded: `{}` is a valid body there, for a runnable that
# takes no arguments.
if body_schema and request_body.get('required') and body_schema.get('properties'):
body_schema['minProperties'] = 1
# Sanitize empty schemas for JSON Schema draft 2020-12 compliance
path_params_schema = sanitize_empty_schemas(path_params_schema)
query_params_schema = sanitize_empty_schemas(query_params_schema)
body_schema = sanitize_empty_schemas(body_schema)
# Convert enums to descriptions for client compatibility
path_params_schema = convert_enums_to_descriptions(path_params_schema)
query_params_schema = convert_enums_to_descriptions(query_params_schema)
body_schema = convert_enums_to_descriptions(body_schema)
# Detect overlapping property names across schemas and rename with suffixes
path_keys = set(path_params_schema['properties'].keys()) if path_params_schema and path_params_schema.get('properties') else set()
query_keys = set(query_params_schema['properties'].keys()) if query_params_schema and query_params_schema.get('properties') else set()
body_keys = set(body_schema['properties'].keys()) if body_schema and body_schema.get('properties') else set()
conflicts = (path_keys & query_keys) | (path_keys & body_keys) | (query_keys & body_keys)
query_field_renames = {}
body_field_renames = {}
for field in conflicts:
# The path parameter keeps the plain name: it identifies the item, is what a
# caller reaches for first, and matches the non-colliding endpoints (`getFlowByPath`
# takes `path`). Only the other locations carry a suffix.
schemas_and_renames = [
(query_params_schema, query_keys, '__query', query_field_renames),
(body_schema, body_keys, '__body', body_field_renames),
]
for schema, keys, suffix, renames_map in schemas_and_renames:
if field in keys and schema and 'properties' in schema:
new_name = field + suffix
# Rename in properties
schema['properties'][new_name] = schema['properties'].pop(field)
# Update description to clarify the renamed field
if 'description' not in schema['properties'][new_name]:
schema['properties'][new_name] = dict(schema['properties'][new_name])
prop = schema['properties'][new_name]
if isinstance(prop, dict):
existing_desc = prop.get('description', '')
location = suffix.lstrip('_')
if not existing_desc:
prop['description'] = f"({location} parameter)"
else:
prop['description'] = f"{existing_desc} ({location} parameter)"
# Rename in required array
if 'required' in schema and field in schema['required']:
schema['required'] = [new_name if r == field else r for r in schema['required']]
# Store the reverse mapping: renamed -> original
renames_map[new_name] = field
# A body field colliding with a same-named path parameter (`path` on the update
# endpoints) holds the new value and differs only when moving the item, so it must
# stay optional; the server defaults it from the URL path when the caller omits it.
if field in path_keys and field in body_keys and body_schema:
body_name = field + '__body'
if 'required' in body_schema:
body_schema['required'] = [r for r in body_schema['required'] if r != body_name]
prop = body_schema['properties'].get(body_name)
if isinstance(prop, dict):
existing_desc = prop.get('description', '').rstrip('. ')
prop['description'] = (
f"{existing_desc}. Defaults to `{field}` when omitted; "
f"set it only to change the {field}."
).lstrip('. ')
# Return None for empty schemas
path_params_schema = path_params_schema if path_params_schema and path_params_schema.get('properties') else None
query_params_schema = query_params_schema if query_params_schema and query_params_schema.get('properties') else None
return (path_params_schema, query_params_schema, body_schema, query_field_renames, body_field_renames)
# Cache for loaded external files
_external_file_cache: Dict[str, Dict[str, Any]] = {}
def load_external_file(file_path: str, base_path: str) -> Optional[Dict[str, Any]]:
"""Load an external YAML file relative to the base path."""
if file_path in _external_file_cache:
return _external_file_cache[file_path]
try:
import yaml
from pathlib import Path
# Resolve the path relative to the base file
base_dir = Path(base_path).parent
full_path = (base_dir / file_path).resolve()
with open(full_path, 'r', encoding='utf-8') as f:
content = yaml.safe_load(f)
_external_file_cache[file_path] = content
return content
except Exception as e:
print(f"Warning: Could not load external file {file_path}: {e}", file=sys.stderr)
return None
def resolve_ref(ref_path: str, spec: Dict[str, Any], base_path: str = "") -> tuple:
"""Resolve a $ref path to the actual schema definition.
Handles both internal refs (#/...) and external file refs (file.yaml#/...).
Returns a tuple of (resolved_schema, resolved_spec) where resolved_spec is the spec
that should be used for resolving any nested refs within the resolved schema.
"""
# Check if this is an external file reference
if '#' in ref_path and not ref_path.startswith('#'):
# External file reference: "../../openflow.openapi.yaml#/components/schemas/Retry"
file_part, fragment = ref_path.split('#', 1)
external_spec = load_external_file(file_part, base_path)
if external_spec is None:
return None, spec
# Resolve the fragment within the external file, and return external_spec for nested refs
resolved, _ = resolve_ref('#' + fragment, external_spec, base_path)
return resolved, external_spec
if not ref_path.startswith('#/'):
return None, spec
# Remove the '#/' prefix and split by '/'
path_parts = ref_path[2:].split('/')
# Navigate through the spec following the path
current = spec
for part in path_parts:
if isinstance(current, dict) and part in current:
current = current[part]
else:
return None, spec
return (current if isinstance(current, dict) else None), spec
def resolve_schema_refs(schema: Dict[str, Any], spec: Dict[str, Any], base_path: str = "", _visited_refs: Optional[set] = None) -> Dict[str, Any]:
"""Recursively resolve all $ref references in a schema."""
if _visited_refs is None:
_visited_refs = set()
if not isinstance(schema, dict):
return schema
# If this is a $ref, resolve it
if '$ref' in schema:
ref_path = schema['$ref']
if ref_path in _visited_refs:
# Circular reference detected - return empty object to break the cycle
return {"type": "object"}
_visited_refs = _visited_refs | {ref_path}
resolved, resolved_spec = resolve_ref(ref_path, spec, base_path)
if resolved:
# Recursively resolve any refs in the resolved schema using the appropriate spec
return resolve_schema_refs(resolved, resolved_spec, base_path, _visited_refs)
else:
print(f"Warning: Could not resolve $ref: {ref_path}")
return schema
# Recursively process all values in the schema
resolved_schema = {}
for key, value in schema.items():
if isinstance(value, dict):
resolved_schema[key] = resolve_schema_refs(value, spec, base_path, _visited_refs)
elif isinstance(value, list):
resolved_schema[key] = [
resolve_schema_refs(item, spec, base_path, _visited_refs) if isinstance(item, dict) else item
for item in value
]
else:
resolved_schema[key] = value
return resolved_schema
def convert_enums_to_descriptions(schema: Any) -> Any:
"""Recursively convert enum arrays into description text to avoid client compatibility issues."""
if isinstance(schema, list):
return [convert_enums_to_descriptions(item) for item in schema]
if not isinstance(schema, dict):
return schema
result = {}
enum_value = None
# First pass: copy all non-enum keys so 'description' is available before enum processing
for key, value in schema.items():
if key == 'enum':
enum_value = value
else:
result[key] = convert_enums_to_descriptions(value)
# Second pass: process enum using the already-copied description
if enum_value is not None:
values_str = ', '.join(str(v) for v in enum_value)
existing = result.get('description', '')
enum_desc = f"Possible values: {values_str}"
result['description'] = f"{existing}. {enum_desc}" if existing else enum_desc
return result
def sanitize_empty_schemas(schema: Any) -> Any:
"""Replace empty {} schemas with valid JSON Schema draft 2020-12 equivalents.
In OpenAPI, {} means 'any value' but strict JSON Schema validators (e.g. Claude's API)
reject empty objects. This converts them to proper schemas.
"""
if isinstance(schema, list):
return [sanitize_empty_schemas(item) for item in schema]
if not isinstance(schema, dict):
return schema
result = {}
for key, value in schema.items():
if key == 'additionalProperties' and isinstance(value, dict) and len(value) == 0:
result[key] = True
elif key == 'properties' and isinstance(value, dict):
# properties is a map of name -> schema; sanitize each property schema
result[key] = {
k: {"type": "object"} if isinstance(v, dict) and len(v) == 0 else sanitize_empty_schemas(v)
for k, v in value.items()
}
else:
result[key] = sanitize_empty_schemas(value)
return result
def extract_request_body_schema(request_body: Dict[str, Any], spec: Dict[str, Any], base_path: str = "") -> Optional[Dict[str, Any]]:
"""Extract request body schema from OpenAPI requestBody definition and resolve refs."""
if not request_body:
return None
content = request_body.get('content', {})
json_content = content.get('application/json', {})
schema = json_content.get('schema', {})
if schema:
# Resolve any $ref references in the schema
return resolve_schema_refs(schema, spec, base_path)
return None
def http_method_to_rust(method: str) -> str:
"""Convert HTTP method string to Rust http::Method enum."""
method_map = {
'get': 'http::Method::GET',
'post': 'http::Method::POST',
'put': 'http::Method::PUT',
'delete': 'http::Method::DELETE',
'patch': 'http::Method::PATCH',
'head': 'http::Method::HEAD',
'options': 'http::Method::OPTIONS'
}
return method_map.get(method.lower(), f'http::Method::{method.upper()}')
def schema_to_rust_value(schema: Optional[Dict[str, Any]]) -> str:
"""Convert a schema dict to a Rust serde_json::json! expression."""
if schema is None:
return "None"
# ensure_ascii=False: json.dumps would escape a non-ASCII character in a
# description as \uXXXX, which Rust rejects — its string literals spell it
# \u{XXXX}. Emitting the character itself is valid in both.
return f"Some(serde_json::json!({json.dumps(schema, indent=8, ensure_ascii=False)}))"
def build_tool_description(operation: Dict[str, Any], method: str, path: str) -> str:
"""Build the MCP tool description from OpenAPI summary and description.
`x-mcp-tool-description` stands in for the operation's own description, for a route
whose two audiences need different text: the description documents the endpoint,
including fields like `parent_hash` that `x-mcp-tool-include-fields` deliberately
keeps out of the tool, and naming one there tells an agent to send what its schema
does not offer.
"""
summary = operation.get('summary', '').strip()
description = (
operation.get('x-mcp-tool-description') or operation.get('description', '')
).strip()
if summary and description:
return f"{summary}: {description}".rstrip('.!? ')
if summary:
return summary
if description:
return description.rstrip('.!? ')
return f'{method.upper()} {path}'
def find_mcp_tools(spec: Dict[str, Any]) -> List[Dict[str, Any]]:
"""Find all endpoints marked with x-mcp-tool: true."""
tools = []
paths = spec.get('paths', {})
for path, path_item in paths.items():
for method, operation in path_item.items():
if isinstance(operation, dict) and operation.get('x-mcp-tool') is True:
# Extract tool information
tool = {
# The name an agent sees. Defaults to the operationId, which
# every generated client is keyed on, so an endpoint whose
# tool should read differently overrides it here rather than
# by renaming the operation.
'name': operation.get('x-mcp-tool-name') or operation.get('operationId', f"{method}_{path.replace('/', '_').replace('{', '').replace('}', '')}"),
'description': build_tool_description(operation, method, path),
'instructions': operation.get('x-mcp-instructions', ''),
'path': path,
'method': method.upper(),
'parameters': operation.get('parameters', []),
'requestBody': operation.get('requestBody'),
'required_fields': operation.get('x-mcp-required-fields', []),
'include_fields': operation.get('x-mcp-tool-include-fields'),
'opaque_fields': operation.get('x-mcp-tool-opaque-fields'),
'include_query_params': operation.get('x-mcp-tool-include-query-params'),
}
tools.append(tool)
# A tool name used to be an operationId, which OpenAPI already keeps unique.
# `x-mcp-tool-name` gives that up, and a duplicate would be silent: a token's
# `mcp:endpoints:<name>` resolves by first match, so which endpoint it reaches
# would depend on the order of this file.
names = [t['name'] for t in tools]
duplicates = sorted({n for n in names if names.count(n) > 1})
if duplicates:
raise ValueError(f"duplicate MCP tool name(s): {', '.join(duplicates)}")
return tools
def generate_typescript_code(tools: List[Dict[str, Any]], spec: Dict[str, Any], base_path: str = "") -> str:
"""Generate TypeScript code with MCP endpoint tools.
This catalogue only feeds the frontend's MCP scope picker, which reads names and
methods.
"""
if not tools:
return """// Auto-generated MCP tools from OpenAPI specification
// This file is generated by generate_mcp_tools.py - DO NOT EDIT MANUALLY
export interface EndpointTool {
name: string;
description: string;
instructions: string;
path: string;
method: string;
pathParamsSchema?: object;
queryParamsSchema?: object;
bodySchema?: object;
}
export const mcpEndpointTools: EndpointTool[] = [];
"""
tool_definitions = []
for tool in tools:
tool_name = tool['name']
description = tool['description'].replace('"', '\\"').replace('\n', '\\n')
instructions = tool['instructions'].replace('"', '\\"').replace('\n', '\\n')
path = tool['path']
method = tool['method'].upper()
# Generate separate schemas
path_params_schema, query_params_schema, body_schema, query_field_renames, body_field_renames = extract_separate_schemas(
tool['parameters'], tool['requestBody'], spec, tool['required_fields'], base_path,
tool.get('include_fields'), tool.get('opaque_fields'), tool.get('include_query_params')
)
# Convert schemas to TypeScript - use 'as const' for better type inference
path_params_ts = json.dumps(path_params_schema, indent=8) if path_params_schema else "undefined"
query_params_ts = json.dumps(query_params_schema, indent=8) if query_params_schema else "undefined"
body_schema_ts = json.dumps(body_schema, indent=8) if body_schema else "undefined"
query_field_renames_ts = json.dumps(query_field_renames, indent=8) if query_field_renames else "undefined"
body_field_renames_ts = json.dumps(body_field_renames, indent=8) if body_field_renames else "undefined"
# Generate tool definition
tool_def = f""" {{
name: "{tool_name}",
description: "{description}",
instructions: "{instructions}",
path: "{path}",
method: "{method}",
pathParamsSchema: {path_params_ts},
queryParamsSchema: {query_params_ts},
bodySchema: {body_schema_ts},
queryFieldRenames: {query_field_renames_ts},
bodyFieldRenames: {body_field_renames_ts}
}}"""
tool_definitions.append(tool_def)
# Combine everything
tool_definitions_str = ",\n".join(tool_definitions)
typescript_code = f"""// Auto-generated MCP tools from OpenAPI specification
// This file is generated by generate_mcp_tools.py - DO NOT EDIT MANUALLY
export interface EndpointTool {{
name: string;
description: string;
instructions: string;
path: string;
method: string;
pathParamsSchema?: object;
queryParamsSchema?: object;
bodySchema?: object;
queryFieldRenames?: Record<string, string>;
bodyFieldRenames?: Record<string, string>;
}}
export const mcpEndpointTools: EndpointTool[] = [
{tool_definitions_str}
];
"""
return typescript_code
def generate_rust_code(tools: List[Dict[str, Any]], spec: Dict[str, Any], base_path: str = "") -> str:
"""Generate the complete Rust code with MCP tools."""
if not tools:
return f"""// No MCP tools found in the OpenAPI specification
{IMPORTS}
pub fn all_tools() -> Vec<EndpointTool> {{
vec![]
}}
"""
tool_definitions = []
for tool in tools:
tool_name = tool['name']
description = tool['description']
instructions = tool['instructions']
path = tool['path']
method = tool['method'].upper()
# Generate separate schemas
path_params_schema, query_params_schema, body_schema, query_field_renames, body_field_renames = extract_separate_schemas(
tool['parameters'], tool['requestBody'], spec, tool['required_fields'], base_path,
tool.get('include_fields'), tool.get('opaque_fields'), tool.get('include_query_params')
)
path_params_rust = schema_to_rust_value(path_params_schema)
query_params_rust = schema_to_rust_value(query_params_schema)
body_schema_rust = schema_to_rust_value(body_schema)
query_field_renames_rust = schema_to_rust_value(query_field_renames if query_field_renames else None)
body_field_renames_rust = schema_to_rust_value(body_field_renames if body_field_renames else None)
# Generate tool definition
tool_def = f""" EndpointTool {{
name: Cow::Borrowed("{tool_name}"),
description: Cow::Borrowed("{description}"),
instructions: Cow::Borrowed("{instructions}"),
path: Cow::Borrowed("{path}"),
method: Cow::Borrowed("{method}"),
path_params_schema: {path_params_rust},
query_params_schema: {query_params_rust},
body_schema: {body_schema_rust},
query_field_renames: {query_field_renames_rust},
body_field_renames: {body_field_renames_rust},
}}"""
tool_definitions.append(tool_def)
# Combine everything
tool_definitions_str = ",\n".join(tool_definitions)
rust_code = f"""// Auto-generated MCP tools from OpenAPI specification
// This file is generated by generate_mcp_tools.py - DO NOT EDIT MANUALLY
{IMPORTS}
pub fn all_tools() -> Vec<EndpointTool> {{
vec![
{tool_definitions_str}
]
}}
"""
return rust_code
def main():
"""Main function to parse OpenAPI and generate Rust and TypeScript code."""
script_dir = Path(__file__).parent
backend_dir = script_dir.parent
project_dir = backend_dir.parent
openapi_file = backend_dir / "windmill-api" / "openapi.yaml"
rust_output_file = backend_dir / "windmill-api" / "src" / "mcp" / "auto_generated_endpoints.rs"
ts_output_file = project_dir / "frontend" / "src" / "lib" / "mcpEndpointTools.ts"
if not openapi_file.exists():
print(f"OpenAPI file not found: {openapi_file}", file=sys.stderr)
sys.exit(1)
print(f"Loading OpenAPI specification from: {openapi_file}")
spec = load_openapi_spec(str(openapi_file))
print("Searching for endpoints with x-mcp-tool: true...")
tools = find_mcp_tools(spec)
if tools:
print(f"Found {len(tools)} MCP tool(s):")
for tool in tools:
print(f" - {tool['name']}: {tool['method']} {tool['path']}")
else:
print("No MCP tools found (no endpoints with x-mcp-tool: true)")
# Generate and write Rust code
print(f"Generating Rust code...")
rust_code = generate_rust_code(tools, spec, str(openapi_file))
print(f"Writing Rust code to: {rust_output_file}")
rust_output_file.parent.mkdir(parents=True, exist_ok=True)
with open(rust_output_file, 'w', encoding='utf-8') as f:
f.write(rust_code)
# Generate and write TypeScript code
print(f"Generating TypeScript code...")
typescript_code = generate_typescript_code(tools, spec, str(openapi_file))
print(f"Writing TypeScript code to: {ts_output_file}")
ts_output_file.parent.mkdir(parents=True, exist_ok=True)
with open(ts_output_file, 'w', encoding='utf-8') as f:
f.write(typescript_code)
print("Done!")
if __name__ == "__main__":
main()