feat: update project status and architecture (#8182)

* feat: update readme

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* fix: image link

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* chore: style

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* feat: adds agent onboarding

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* fix: address by CR

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* fix: link

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

---------

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

README.md

@@ -9,7 +9,7 @@
 <h2 align="center">One database for metrics, logs, and traces<br/>
 replacing Prometheus, Loki, and Elasticsearch</h2>
 
->  The unified OpenTelemetry backend — with SQL + PromQL on object storage.
+> The unified OpenTelemetry backend — with SQL + PromQL on object storage.
 
 <div align="center">
 <h3 align="center">
@@ -30,11 +30,11 @@ replacing Prometheus, Loki, and Elasticsearch</h2>
 <a href="https://github.com/GreptimeTeam/greptimedb/actions/workflows/develop.yml">
 <img src="https://github.com/GreptimeTeam/greptimedb/actions/workflows/develop.yml/badge.svg" alt="GitHub Actions"/>
 </a>
-<a href="https://codecov.io/gh/GrepTimeTeam/greptimedb">
-<img src="https://codecov.io/gh/GrepTimeTeam/greptimedb/branch/main/graph/badge.svg?token=FITFDI3J3C" alt="Codecov"/>
+<a href="https://codecov.io/gh/GreptimeTeam/greptimedb">
+<img src="https://codecov.io/gh/GreptimeTeam/greptimedb/branch/main/graph/badge.svg?token=FITFDI3J3C" alt="Codecov"/>
 </a>
-<a href="https://github.com/greptimeTeam/greptimedb/blob/main/LICENSE">
-<img src="https://img.shields.io/github/license/greptimeTeam/greptimedb" alt="License"/>
+<a href="https://github.com/GreptimeTeam/greptimedb/blob/main/LICENSE">
+<img src="https://img.shields.io/github/license/GreptimeTeam/greptimedb" alt="License"/>
 </a>
 
 <br/>
@@ -51,7 +51,8 @@ replacing Prometheus, Loki, and Elasticsearch</h2>
 </div>
 
 - [Introduction](#introduction)
-- [⭐ Key Features](#features)
+- [Overview](#overview)
+- [Features](#features)
 - [How GreptimeDB Compares](#how-greptimedb-compares)
 - [Architecture](#architecture)
 - [Try GreptimeDB](#try-greptimedb)
@@ -69,37 +70,47 @@ replacing Prometheus, Loki, and Elasticsearch</h2>
 
 **GreptimeDB** is an open-source observability database built for [Observability 2.0](https://docs.greptime.com/user-guide/concepts/observability-2/) — treating metrics, logs, and traces as one unified data model (wide events) instead of three separate pillars.
 
-Use it as the single OpenTelemetry backend — replacing Prometheus, Loki, and Elasticsearch with one database built on object storage. Query with SQL and PromQL, scale without pain, cut costs up to 50x.
+Use it as the single OpenTelemetry backend — replacing Prometheus, Loki, and Elasticsearch with one database built on object storage. Query with SQL and PromQL, scale without pain, cut costs up to 50×.
+
+## Overview
+
+A quick overview of what GreptimeDB ingests, how it connects to other systems, and what its distributed engine lets you do.
+
+<p align="center">
+  <a href="https://github.com/GreptimeTeam/greptimedb/raw/main/docs/overview.png" target="_blank" rel="noopener">
+    <img alt="GreptimeDB Overview" src="docs/overview.png" width="900px">
+  </a>
+</p>
 
 ## Features
 
-|   Feature  | Description |
-| --------- | ----------- |
-| Drop-in replacement | [PromQL](https://docs.greptime.com/user-guide/query-data/promql/), [Prometheus remote write](https://docs.greptime.com/user-guide/ingest-data/for-observability/prometheus/), [Jaeger](https://docs.greptime.com/user-guide/query-data/jaeger/), and [OpenTelemetry](https://docs.greptime.com/user-guide/ingest-data/for-observability/opentelemetry/) native. Use as your single backend for all three signals, or migrate one at a time.|
-| 50x lower cost | Object storage (S3, GCS, Azure Blob etc.) as [primary storage](https://docs.greptime.com/user-guide/deployments-administration/configuration/#storage-options). Compute-storage separation scales without pain.|
-| SQL + PromQL | Monitor with [PromQL](https://docs.greptime.com/user-guide/query-data/promql), analyze with [SQL](https://docs.greptime.com/user-guide/query-data/sql). One database replaces Prometheus + your data warehouse.|
-| Sub-second at PB-EB scale | Columnar engine with [fulltext, inverted, and skipping indexes](https://docs.greptime.com/user-guide/manage-data/data-index). Written in Rust.|
+| Feature | Description |
+|---------|-------------|
+| **Observability 2.0 native** | Logs, metrics, and traces in one engine with [SQL + PromQL](https://docs.greptime.com/user-guide/query-data/overview/). Native [OpenTelemetry](https://docs.greptime.com/user-guide/ingest-data/for-observability/opentelemetry/), [Prometheus remote write](https://docs.greptime.com/user-guide/ingest-data/for-observability/prometheus/), and [Jaeger](https://docs.greptime.com/user-guide/query-data/jaeger/). Migrate one signal at a time, or use as a single backend. |
+| **Elastic compute-storage separation** | Scale reads independently with horizontal replicas. Serve high-concurrency workloads from dashboards, alerting, and AI agents — without resharding or data migration. |
+| **Sub-second on PB–EB-scale data** | Columnar engine with [fulltext, inverted, and skipping indexes](https://docs.greptime.com/user-guide/manage-data/data-index). Written in Rust. Designed for high-concurrency point queries, not just analytical scans. |
+| **50× lower cost** | Object storage (S3, GCS, Azure Blob) as [primary storage](https://docs.greptime.com/user-guide/deployments-administration/configuration/#storage-options), with a tiered cache (memory + local disk) to keep writes and queries fast. |
 
-  ✅ **Perfect for:**
-  * Replacing Prometheus + Loki + Elasticsearch with one database
+**Perfect for:**
+  * Replacing Prometheus + Loki + Elasticsearch with a single observability backend
   * Scaling past Prometheus — high cardinality, long-term storage, no Thanos/Mimir overhead
-  * Cutting observability costs with object storage (up to 50x savings on traces, 30% on logs)
-  * AI/LLM observability — store and analyze high-volume conversation data, agent traces, and token metrics via [OpenTelemetry GenAI conventions](https://opentelemetry.io/docs/specs/semconv/gen-ai/)
+  * AI/agent workloads — store GenAI telemetry ([OTel GenAI conventions](https://opentelemetry.io/docs/specs/semconv/gen-ai/)), and serve high-concurrency reads from SRE/developer agents via horizontal read replicas
+  * Cutting observability costs with object storage (up to 50× savings on traces, 30% on logs)
   * Edge-to-cloud observability with unified APIs on resource-constrained devices
 
-> **Why Observability 2.0?** The three-pillar model (separate databases for metrics, logs, traces) creates data silos and operational complexity. GreptimeDB treats all observability data as timestamped wide events in a single columnar engine — enabling cross-signal SQL JOINs, eliminating redundant infrastructure, and naturally supporting emerging workloads like AI agent observability. Read more: [Observability 2.0 and the Database for It](https://greptime.com/blogs/2025-04-25-greptimedb-observability2-new-database).
+> **Why Observability 2.0?** Three separate databases for metrics, logs, and traces means three storage layers, three query languages, and three sets of dashboards. GreptimeDB stores all three as timestamped wide events in one columnar engine — JOIN across signals in SQL, run one stack instead of three, and ingest AI agent telemetry the same way. Read more: [Observability 2.0 and the Database for It](https://greptime.com/blogs/2025-04-25-greptimedb-observability2-new-database).
 
 Learn more in [Why GreptimeDB](https://docs.greptime.com/user-guide/concepts/why-greptimedb).
 
 ## How GreptimeDB Compares
 
-| Feature | GreptimeDB | Prometheus / Thanos / Mimir | Grafana Loki | Elasticsearch |
+| Capability | GreptimeDB | Prometheus / Thanos / Mimir | Grafana Loki | Elasticsearch |
 |---|---|---|---|---|
 | Data types | Metrics, logs, traces | Metrics only | Logs only | Logs, traces |
 | Query language | SQL + PromQL | PromQL | LogQL | Query DSL |
 | Storage | Native object storage (S3, etc.) | Local disk + object storage (Thanos/Mimir) | Object storage (chunks) | Local disk |
 | Scaling | Compute-storage separation, stateless nodes | Federation / Thanos / Mimir — multi-component, ops heavy | Stateless + object storage | Shard-based, ops heavy |
-| Cost efficiency | Up to 50x lower storage | High at scale | Moderate | High (inverted index overhead) |
+| Cost efficiency | Up to 50× lower storage cost | High at scale | Moderate | High (inverted index overhead) |
 | OpenTelemetry | Native (metrics + logs + traces) | Partial (metrics only) | Partial (logs only) | Via instrumentation |
 
 **Benchmarks:**
@@ -110,19 +121,26 @@ Learn more in [Why GreptimeDB](https://docs.greptime.com/user-guide/concepts/why
 ## Architecture
 
 GreptimeDB can run in two modes:
-* **Standalone Mode** - Single binary for development and small deployments
-* **Distributed Mode** - Separate components for production scale:
-  - Frontend: Query processing and protocol handling
-  - Datanode: Data storage and retrieval
-  - Metasrv: Metadata management and coordination
-  
-Read the [architecture](https://docs.greptime.com/contributor-guide/overview/#architecture) document. [DeepWiki](https://deepwiki.com/GreptimeTeam/greptimedb/1-overview) provides an in-depth look at GreptimeDB:
-  <img alt="GreptimeDB System Overview" src="docs/architecture.png">
+* **Standalone** — single binary for development and small deployments.
+* **Distributed** — four components, each independently scalable:
+  - **Frontend** — protocol entry (OTel, Prometheus, MySQL/PostgreSQL, gRPC, ingestion APIs for Elasticsearch/InfluxDB/Loki) and the distributed query engine. Stateless, scales horizontally.
+  - **Datanode** — region engine with WAL, memtable, SST, cache, compaction, and indexes. Persists data to object storage. Elastic.
+  - **Metasrv** — metadata, routing, repartitioning, autopilot, and security. Backed by a pluggable KV layer (etcd or RDS).
+  - **Flownode** (optional) — continuous flow computation (streaming and materialized views).
+
+For deeper coverage, see the [architecture doc](https://docs.greptime.com/contributor-guide/overview/#architecture) or [DeepWiki](https://deepwiki.com/GreptimeTeam/greptimedb/1-overview).
+
+<a href="https://github.com/GreptimeTeam/greptimedb/raw/main/docs/architecture.png" target="_blank" rel="noopener">
+  <img alt="GreptimeDB System Overview" src="https://cdn.jsdelivr.net/gh/GreptimeTeam/greptimedb@main/docs/architecture.png">
+</a>
 
 ## Try GreptimeDB
 
-```shell
-docker pull greptime/greptimedb
+**For AI agents** — paste this prompt into your agent:
+
+```text
+Read https://docs.greptime.com/SKILL.md and follow the instructions
+to deploy, configure, ingest, and query GreptimeDB.
 ```
 
 ```shell
@@ -153,20 +171,30 @@ Read more in the [full Install Guide](https://docs.greptime.com/getting-started/
 ## Build From Source
 
 **Prerequisites:**
-* [Rust toolchain](https://www.rust-lang.org/tools/install) (nightly)
+* [Rust toolchain](https://www.rust-lang.org/tools/install) — nightly, pinned by [`rust-toolchain.toml`](https://github.com/GreptimeTeam/greptimedb/blob/main/rust-toolchain.toml)
 * [Protobuf compiler](https://grpc.io/docs/protoc-installation/) (>= 3.15)
-* C/C++ building essentials, including `gcc`/`g++`/`autoconf` and glibc library (eg. `libc6-dev` on Ubuntu and `glibc-devel` on Fedora)
-* Python toolchain (optional): Required only if using some test scripts.
+* C/C++ building essentials: `gcc` / `g++` / `autoconf` and the glibc dev package (`libc6-dev` on Ubuntu, `glibc-devel` on Fedora)
+* Python toolchain (optional, only for some test scripts)
 
-**Build and Run:**
+**Build and run:**
 ```bash
-make
-cargo run -- standalone start
+make                          # build greptime binary
+cargo run -- standalone start # start in standalone mode
 ```
 
+**Common dev commands:**
+```bash
+make fmt            # format Rust code
+make clippy         # lint (fails on warnings)
+make test           # unit + integration tests (uses cargo-nextest)
+make sqlness-test   # SQL regression tests
+```
+
+See the [Contribution Guidelines](CONTRIBUTING.md) for the full developer workflow.
+
 ## Tools & Extensions
 
-- **Kubernetes**: [GreptimeDB Operator](https://github.com/GrepTimeTeam/greptimedb-operator)
+- **Kubernetes**: [GreptimeDB Operator](https://github.com/GreptimeTeam/greptimedb-operator)
 - **Helm Charts**: [Greptime Helm Charts](https://github.com/GreptimeTeam/helm-charts)
 - **Dashboard**: [Web UI](https://github.com/GreptimeTeam/dashboard)
 - **gRPC Ingester**: [Go](https://github.com/GreptimeTeam/greptimedb-ingester-go), [Java](https://github.com/GreptimeTeam/greptimedb-ingester-java), [C++](https://github.com/GreptimeTeam/greptimedb-ingester-cpp), [Erlang](https://github.com/GreptimeTeam/greptimedb-ingester-erl), [Rust](https://github.com/GreptimeTeam/greptimedb-ingester-rust), [.NET](https://github.com/GreptimeTeam/greptimedb-ingester-dotnet)
@@ -175,18 +203,11 @@ cargo run -- standalone start
 
 ## Project Status
 
-> **Status:** [v1.0 GA](https://github.com/GreptimeTeam/greptimedb/releases/tag/v1.0.0) — generally available and production-ready! 🎉
+GreptimeDB is at [v1.0 GA](https://github.com/GreptimeTeam/greptimedb/releases/tag/v1.0.0) with stable APIs and regular releases. It runs in production at scale — [OceanBase Cloud](https://greptime.com/blogs/2025-07-22-user-case-obcloud-log-management-greptimedb) operates 80+ GreptimeDB clusters managing 300 TB of logs, cutting log storage cost by 60% after migrating from Grafana Loki. See more in [case studies](https://greptime.com/blogs/?category=Use%20Case).
 
-- Deployed in production handling billions of data points daily
-- Stable APIs, actively maintained, with regular releases ([version info](https://docs.greptime.com/nightly/reference/about-greptimedb-version))
+Read the [v1.0 highlights](https://greptime.com/blogs/2025-11-05-greptimedb-v1-highlights) and [2026 roadmap](https://greptime.com/blogs/2026-02-11-greptimedb-roadmap-2026), or browse the [version reference](https://docs.greptime.com/nightly/reference/about-greptimedb-version).
 
-GreptimeDB v1.0 marks a major milestone — stable APIs, production readiness, and proven performance at scale.
-
-**Learn more:** [v1.0 highlights](https://greptime.com/blogs/2025-11-05-greptimedb-v1-highlights) and [2026 roadmap](https://greptime.com/blogs/2026-02-11-greptimedb-roadmap-2026).
-
-For production use, we recommend v1.0 or later.
-
-If you find this project useful, a ⭐ would mean a lot to us!
+If GreptimeDB is useful to you, please star the repo.
 
 [![Star History Chart](https://api.star-history.com/svg?repos=GreptimeTeam/GreptimeDB&type=Date)](https://www.star-history.com/#GreptimeTeam/GreptimeDB&Date)
 
@@ -216,15 +237,19 @@ We offer enterprise add-ons, services, training, and consulting.
 
 ## Contributing
 
-- Read our [Contribution Guidelines](https://github.com/GreptimeTeam/greptimedb/blob/main/CONTRIBUTING.md).
+- Read our [Contribution Guidelines](CONTRIBUTING.md).
 - Explore [Internal Concepts](https://docs.greptime.com/contributor-guide/overview.html) and [DeepWiki](https://deepwiki.com/GreptimeTeam/greptimedb).
 - Pick up a [good first issue](https://github.com/GreptimeTeam/greptimedb/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) and join the #contributors [Slack](https://greptime.com/slack) channel.
 
 ## Acknowledgement
 
-Special thanks to all contributors! See [AUTHORS.md](https://github.com/GreptimeTeam/greptimedb/blob/main/AUTHOR.md).
+Special thanks to all contributors! See [AUTHOR.md](AUTHOR.md).
 
 - Uses [Apache Arrow™](https://arrow.apache.org/) (memory model)
 - [Apache Parquet™](https://parquet.apache.org/) (file storage)
-- [Apache DataFusion™](https://arrow.apache.org/datafusion/) (query engine)
+- [Apache DataFusion™](https://datafusion.apache.org/) (query engine)
 - [Apache OpenDAL™](https://opendal.apache.org/) (data access abstraction)
+
+---
+
+*All trademarks, logos, and brand names referenced in this README and in the Overview diagram are the property of their respective owners. Their use is for identification purposes only and does not imply endorsement or affiliation.*