ProvelyLangGraph connects to Provely through the MCP server, the CLI, the SDK, the REST API. The agent does the action. Provely verifies the outcome and signs a receipt. LangGraph never holds the verifier credentials.
A person verified the LangGraph capabilities on 2026-09-08. Agent products change monthly. Re-verify before you build.
Source: integration profile langgraph · retrieved 2026-09-08
Which surfaces does LangGraph use?
| Surface | Support | Detail |
|---|---|---|
| MCP server | Supported | transport stdio, http |
| CLI | Supported | Runs through the shell tool of the agent. |
| SDK | Supported | languages python, typescript; two lines, no adapter: LangGraph |
| REST API | Supported | Any HTTP call reaches the control plane. |
Which guidance files does LangGraph read?
Provely ships one Agent Skill for this host, so the agent knows to verify an outcome before it claims done. The renderer writes prompt fragment from one source. A new agent needs a profile, not core code.
Explain: each file, its path and its write mode
| Format | Path | Mode |
|---|---|---|
| prompt fragment | provely/prompt-fragment.md | fragment |
| CI gate workflow | .provely/ci/github-actions.yml | fragment |
How is a false completion claim blocked?
Guidance asks. A hook and the CI gate enforce. A host with neither still receives the verdict, and a person reads it before the work ships.
Explain: what each control does on this host
| Enforcement | Support | Detail |
|---|---|---|
| Advisory guidance | Supported | The instruction files state the rules for every agent. |
| Lifecycle hooks | Supported | tool_call |
| CI gate | Supported | provely verify --wait fails the pipeline unless the verdict is VERIFIED. |
How do I connect LangGraph?
Connect LangGraph to Provely
- Install the CLI.Run
curl -fsSL https://provely.sh/install.sh | sh. On Windows, runirm https://provely.sh/install.ps1 | iex. Each script verifies the signed checksum before it installs the binary. - Register the MCP server.Add the Provely server. Use
provely mcpfor stdio, or the hosted HTTP server with a bearer token. The tools arebegin,verify,status, andreceipt. - Write the guidance files.Run
provely init --agent langgraph. It writesprovely/prompt-fragment.md(fragment),.provely/ci/github-actions.yml(fragment). The guidance carries one rule: a successful tool call is not completion. - Install the hooks.Enable the
tool_callhooks. A hook calls the CLI and blocks a completion claim while an operation is PENDING. - Add the CI gate.Run
provely verify --wait <duration>in the pipeline. The step fails unless the verdict is VERIFIED. Exit codes: 0 VERIFIED, 2 PENDING, 3 FAILED, 4 CONTRADICTED, 5 UNVERIFIABLE, 1 error. - Report the verdict exactly as returned.VERIFIED: "The action is verified complete. Receipt: <id>." PENDING: "The action is accepted but not yet verified. Operation: <id>."
What else does the profile state?
- Verified 2026-09-08: this repository ships the interception point.
provely.instrument(create_react_agent)wraps every tool callable and refuses a call that the policy names no contract for. Read sdks/python/src/provely/guard/langgraph_agent.py and the TypeScript twin. - The interception point is code, not a script. It blocks only after the application calls instrument. An application that never calls it gets advisory guidance and the CI gate.
- Verified 2026-09-08: LangGraph middleware exposes wrap_tool_call, which can stop a tool call before it runs. before_model, after_model, before_agent, and after_agent cannot. Source: https://docs.langchain.com/oss/python/langchain/middleware/custom.
- Verified 2026-09-08: LangGraph reads MCP servers through langchain-mcp-adapters and MultiServerMCPClient, over stdio, streamable HTTP, and SSE. A remote server takes headers with Authorization. Source: https://github.com/langchain-ai/langchain-mcp-adapters.
- Use the langgraph adapter. Wrap a node so the action runs inside an operation. A node that ends while PENDING stores the operation id in the graph state.
LangGraph keeps its action credentials, and no surface returns the verifier credentials to it. Read the credential boundary. An operation outlives the session that opened it. Read the API reference.
Which host versions does the profile cover?
>=1.0.0. The integrations team last verified the profile with langgraph 1.2.11 of 2026-08-11 and @langchain/langgraph 1.4.14 on 2026-09-08.