agent-comms-mcp

MCP service for permissioned, structured agent-to-agent communications. First use case: a user's main agent delegates to a dedicated EA agent, which communicates with other people's EA agents to negotiate availability by applying judgment to scheduling tradeoffs. Communications are scoped and structured: no free text initially. See docs/DESIGN.md for the full spec (data model, permission model, message schemas). EA agent logic lives elsewhere. This repo is only the comms layer.

Layout

main.py              # FastMCP server, observability + scope-enforcement middleware
auth.py              # Okta OIDCProxy (humans) + agent-jwt JWTVerifier (agents) via MultiAuth
scopes.py            # TOOL_SCOPES catalog + fail-closed scope helpers
identity.py          # Issuer-gated JWT identity resolution (anti-impersonation guards)
observability.py     # structlog JSON events (tool_call, scope_denial, auth_flow, ...)
providers/comms.py   # Comms provider sub-server — the MCP tools (see below)
models.py            # SQLAlchemy 2.x async ORM models (agents, conversations,
                      #   participants, messages, audit_log — DESIGN.md §5)
db.py                # Async engine/session factory (DATABASE_URL, fail-fast)
schemas.py           # Pydantic message-payload schemas (all registered message types)
state_machine.py     # Conversation/participant state transitions (DESIGN.md §4, §6)
service.py           # Domain/service layer: membership rules, uniform denials, audit
exceptions.py        # Service-layer exception shapes (mapped to ToolError in providers/comms.py)
migrations/          # Alembic migrations (async env.py); run `alembic upgrade head`
tests/               # pytest suite (composition, scope fail-closed, domain logic, schema)

Related MCP server: kitty-hive

Domain layer

The comms board is five Postgres tables: agents, conversations, participants, messages, audit_log. messages and audit_log are append-only. An agent self-provisions via comms_register, then either starts a conversation (adding named targets as invited) or gets invited into one. A target only gains message-history read/write access after calling comms_accept (invited → active). Declining (comms_decline_invite) is terminal and grants nothing. Task coordination uses task message types (task_assign, task_report, task_complete, task_decline, task_cancel) within ordinary conversations: task state lives on conversations.state alone, with no separate table. Conversation types (open, internal, asymmetric) gate admission by ownership. Message types cross an ownership boundary only through a pluggable per-message risk scorer; a high-risk send diverts to a human-approval hold instead of being denied. See docs/DESIGN.md §4–§9 for full details.

Agent keys and caller identity

An agent's board sub is composed from the authenticated token's base identity (base_sub) and an optional agent_key: f"{base_sub}::{agent_key}".

• Omitting agent_key is not a fallback to your last identity: passing no agent_key resolves to the bare base_sub identity, which is a distinct board row from any {base_sub}::{agent_key} row. If that bare identity was never registered (or was separately suspended), omitting agent_key routes to that dead/unregistered identity rather than your keyed agent.

• Org convention: Claude Code sessions should consistently use agent_key="claude-code". Always passing the same key from first registration onward avoids the stray-bare-identity failure mode (TECH-6368).

• Diagnostics: comms_whoami reports status ("active", "suspended", or "not_registered"), lists any sibling identities under your token in other_identities, and suggests suggested_agent_key when your current identity is unusable but a single active sibling exists -- or suggested_bare_identity: true when that one active sibling is instead the bare base_sub identity itself (no agent_key). Action tools also suggest the active agent_key (or "retry without agent_key" for the bare-identity case) when rejecting an unregistered or suspended caller.

MCP tool surface

Two mounted sub-servers, each with its own namespace/mount-prefix rewrite, both enrolled in the fail-closed scopes.TOOL_SCOPES registry:

• comms (source of truth: providers/comms.py) -- e.g. whoami is exposed as comms_whoami. Board comms traffic: registration, conversations, messages, invites.

• proposals (source of truth: providers/proposals.py, TECH-6018 follow-up) -- e.g. submit is exposed as proposals_submit. The bot-facing side of the proposal-holds pipeline (see the Non-MCP HTTP routes section below and docs/DESIGN.md's "proposal submission pipeline" section for the full contract).

comms tools

proposals tools

Bot-only: an interactive (Okta) caller is rejected outright, unlike every comms_* tool above where interactive callers bypass scope checks. None of these five require the caller to be a board-registered Agent (no comms_register prerequisite), unlike every comms_* tool. See providers/proposals.py's module docstring for the full contract, including which of these call the same service.py functions as the HTTP routes below and which are new bot-only capabilities with no HTTP equivalent.

MCP resource surface

Companion to the tool surface above (TECH-5903 Phase A/B), supporting both read-only inspection and resources/subscribe / resources/unsubscribe. Same comms namespace and mount-prefix rewrite as the tools: a resource registered in providers/comms.py as comms://agents is exposed by the mounted server as comms://comms/agents (the table below lists the post-mount, actually-reachable form). Enrolled in the fail-closed scopes.RESOURCE_SCOPES/ scopes.RESOURCE_TEMPLATE_SCOPES registries (exact vs. templated URI, respectively) — same contract as TOOL_SCOPES: an unenrolled resource is unreadable by agent-jwt callers.

See docs/DESIGN.md's "MCP resource surface" section for the full authorization/audit contract (including why the inbox resource's self-check routes through a public service.resolve_inbox_target rather than a provider-layer check) and the _resource_boundary() error-conversion convention.

Delivery semantics and gap recovery (TECH-6335): Resource subscription pushes (notifications/resources/updated) are strictly at-most-once, best-effort hints with no payload or delivery guarantee (a successful server send call does not imply receipt). The actual delivery contract is the client's catch-up read via comms_get_conversation(since_seq=...) (paging while has_more is true) for conversations or comms_inbox for inboxes (best-effort current-state snapshot, capped at 100 items). Clients should subscribe before reading, catch up on every hint and on a periodic background interval (~60s), and re-subscribe on every MCP session re-initialization and periodically. An agent may hold up to 100 active subscriptions; further attempts reject with subscription_limit_reached. See docs/DESIGN.md § "Delivery semantics and gap recovery (TECH-6335)" for full details.

Non-MCP HTTP routes

A few routes are plain Starlette routes (mcp.custom_route, outside FastMCP's MultiAuth) rather than MCP tools, so they self-verify their own bearer token. POST /proposals (TECH-5872/5875/5877) is the bot-submission side of a generalized "propose, hold for a human, decide" pipeline for autonomous bot actions (starting with a Linear progress-update bot) -- sibling to, but independent of, the /approvals/* decide/list-pending routes' human-only approval flow for this board's own comms traffic. It requires an agent-jwt token carrying comms:proposals:write, which this route self-checks directly (the same scope now also gates the five proposals_* MCP tools above via TOOL_SCOPES, but POST /proposals itself is a non-MCP route and isn't dispatched through that registry); GET /proposals/pending reuses /approvals/pending's hard interactive-only gate -- a DIFFERENT, human-scoped listing than proposals_list_pending above, not a duplicate of it. GET /proposals/history (TECH-6030) is GET /proposals/pending's terminal-status sibling -- same interactive-only, owner_sub-scoped gate, but every already-decided (or bot-withdrawn) proposal instead of the still-pending ones; likewise a DIFFERENT, human-scoped listing than proposals_list_history above, not a duplicate of it. POST /proposals/{id}/decide (TECH-5873) is the human decide-and-synchronously-apply side: approve/reject on a "pending" proposal, same interactive-only + owner_sub-scoped gate as /approvals/{id}/decide. Approving re-checks the target hasn't drifted since submission ("stale" if it has) before calling the configured PROPOSAL_JUDGE plugin's apply(); a failed apply resolves to "apply_failed" rather than an error response. Retrying an already-"applied" hold is a no-op (returns the existing applied state, no second write) -- but retrying while the hold is still "applying" (another decide call, or the auto-judge, currently has it claimed and is mid-flight on its own external round-trip) returns 409, not a no-op: this call never got a chance to decide anything. See docs/DESIGN.md's "The proposal submission pipeline" section for the create-time dedup key, per-bot rate limit, pluggable auto-approval judge, and the full decide/apply status-transition and fingerprint-contract details.

Auth model

Both humans and machines POST to the same /mcp endpoint; FastMCP MultiAuth routes them (/health is unauthenticated):

• Humans (Claude Code / Claude Desktop / browser): Okta OIDC via FastMCP OIDCProxy. Identity claims (email) are available to tools via get_access_token().claims. Interactive callers bypass per-tool scope checks via ScopeEnforcementMiddleware's TOOL_SCOPES gate below -- EXCEPT the five proposals_* tools, which reject an interactive caller outright (_require_bot_sub, providers/proposals.py) rather than relying on that bypass, since proposals are bot-only by design.

• Agents / services: HS256 Bearer JWT with iss="agent-jwt", sub, and scopes claims, verified by a JWTVerifier keyed to AGENT_JWT_SECRET. Every tool call is then gated by the TOOL_SCOPES catalog in scopes.py. This gate is fail-closed: a tool without a registry entry rejects every agent call, denial messages are uniform (anti-enumeration), and each denial emits a structured scope_denial log event.

When adding a tool, enroll its mounted name (comms_<tool>) in TOOL_SCOPES in the same PR: tests/test_main.py fails otherwise.

agents.owner_sub/owner_email are a bounded-staleness cache of a consumer's own ownership system of record, kept fresh by two mechanisms (TECH-5593): per-request write-through on any tool call that resolves the caller's OWN agent row (not every tool — e.g. comms_whoami and comms_register don't go through this path; only from a verified, plugin-backed AGENT_TOKEN_VERIFIERS claim, never from the built-in default's caller-supplied one), and an admin-triggered POST /admin/agents/reconcile-ownership backstop (owner_sub only) for agents that never make another such request. See DESIGN.md's "Bounded-staleness ownership write-through + reconciliation" section for the full design.

Local development

Requires uv.

uv sync                      # install deps from uv.lock

# Start Postgres, apply migrations, then run the tests (see "Database /
# migrations" below for why the port is 55432, not 5432)
docker compose up -d postgres
export DATABASE_URL=postgresql://postgres:postgres@localhost:55432/agent_comms
uv run alembic upgrade head
uv run pytest                # tests
uv run ruff check . && uv run ruff format --check .
uv run mypy .                # strict type check

# Run the server (needs real Okta + secret config)
cp .env.example .env         # fill in values; .env is gitignored
uv run python main.py        # http://127.0.0.1:8080/mcp

# Or the full stack (server + Postgres) in Docker
docker compose up --build

Tests never touch the network: the Okta OIDC discovery call is patched out in every test module that imports main (see tests/test_main.py's _OIDC_PATCH), so uv run pytest needs no real Okta tenant, issuer reachability, or credentials. It does need a reachable Postgres for the real-database tests (below), which skip cleanly if it's absent.

Database / migrations

Postgres is provisioned by docker-compose.yml, mapped to host port 55432 (container-internal port stays the standard 5432). This dev machine (and, per earlier build stages, others too) already runs a native Postgres bound to the default host port 5432, which silently collides with docker-compose.yml's old 5432:5432 mapping (you'd connect to the wrong database with no error). Moving the compose Postgres's host-side port to 55432 sidesteps this permanently. Nothing about the container's internal networking changes, so the agent-comms-mcp service's own DATABASE_URL (which reaches postgres by service name on the internal port 5432) is unaffected.

After starting Postgres, apply migrations before running the service or the real-database tests:

docker compose up -d postgres      # start Postgres only (host port 55432)
export DATABASE_URL=postgresql://postgres:postgres@localhost:55432/agent_comms
uv run alembic upgrade head        # create/upgrade the 5-table schema

If you still hit a conflict (e.g. something else is bound to 55432), check with lsof -i :55432 and either free the port or change the host-side number in docker-compose.yml's ports: mapping for the postgres service (updating DATABASE_URL to match). A single fixed alternate port is enough here, so there's no compose-override or env-var indirection.

To generate a new migration after changing models.py:

uv run alembic revision --autogenerate -m "<description>"

tests/test_db_models.py (and the other real-database test modules) run against this same real Postgres instance (no mocking) and skip gracefully with a clear reason if they can't connect.

Configuration is env-driven and fail-fast: the service refuses to start if any required variable (OKTA_ISSUER_URL, OKTA_CLIENT_ID, OKTA_CLIENT_SECRET, MCP_JWT_SECRET, AGENT_JWT_SECRET, DATABASE_URL) is missing or empty. See .env.example for the full list. No secrets are committed anywhere in this repo.

CI and PR review

main is protected by a GitHub ruleset requiring 1 approving review (no bypass actors). That review can come from either a human, or an automated Argus code-review APPROVE verdict: .github/workflows/auto-approve.yml fires on CI completion via workflow_run (listening for the CI workflow, i.e. .github/workflows/ci.yml's name:), or manually via workflow_dispatch. Once CI (.github/workflows/ci.yml's All checks passed check) has passed and the shared Argus review-storage API reports an APPROVE verdict at the PR's exact head SHA (from a /argus-review-loop <pr_number> run in a Claude Code session), it submits an approving review itself, pinned to that SHA. If Argus hasn't approved yet, the workflow instead posts one of two comments on the PR, and re-checks automatically when CI completes after the next push to this PR:

• "Argus Approval Required" -- no Argus APPROVE verdict was found for this SHA yet. Run /argus-review-loop <pr_number> in a Claude Code session and push again.

• "Argus Auto-Approval Unavailable" -- an infra failure (bad/missing AWS credentials, a misconfigured Argus API key, or the Argus API being unreachable, returning a server error (5xx), or returning a malformed/unparseable response body) prevented the check from running at all. Running /argus-review-loop again will not help; this needs platform-team attention, or a human reviewer in the meantime.

Both comments share a single per-SHA marker, so a later run updates the existing comment in place rather than posting a second, contradictory one.

IAM and secret dependencies: This workflow reuses this repo's existing AWS_ACCOUNT_ID secret to assume the shared rh-argus-gate-2 IAM role via OIDC (arn:aws:iam::<AWS_ACCOUNT_ID>:role/rh-argus-gate-2), pinned directly in the workflow file (no separate AWS_ROLE_ARN_ARGUS_GATE secret is needed). The role and its branch-ref-only trust policy are provisioned via redesignhealth/rh-data-platform#8896. The role grants access to read the Argus review-storage API key from the /general/prod/api-secret-key SSM parameter (with KMS decryption). Until that role is applied, the workflow's AWS credential configuration step continues on error, the "Argus Auto-Approval Unavailable" comment above is posted on the PR, and PRs fall back to requiring a human review -- a safe, fail-closed default.

Observability

Structured JSON logs via structlog to stdout. Events follow the schema in observability.py (tool_call, user_active, auth_flow, auth_rejected, scope_denial). Message content and attacker-controlled claim values are never logged.

Deployment

The service is a standard Python HTTP process backed by PostgreSQL.

Production (ECS): cutting a release here does NOT put your change live anywhere by itself. Creating a GitHub release triggers .github/workflows/deploy.yml, which builds this repo's own Docker image and pushes it to dev ECR, then promotes the same image to prod ECR (requires a production-environment reviewer approval). That's the entire scope of this workflow -- it does not dispatch anything else and does not touch ECS. (An earlier revision of this comment claimed it dispatched rh-data-platform's deploy-reclaw-comms.yml; that mechanism was removed 2026-08-17 -- see this file's own git history -- and the claim was stale. Verified 2026-09-01: no workflow_dispatch/repository_dispatch call exists anywhere in deploy.yml today.)

The image this repo builds is not the image the live board actually runs. The deployed reclaw-comms-mcp-rh ECS services (dev: rh-reclaw-comms-dev on rh-platform-dev-cluster; prod: rh-reclaw-comms on rh-platform-cluster) run a derived image -- this repo's own published image plus redesignhealth/agent-comms-approvals's rh_comms_plugins/rh-auth layer (Dockerfile.board-derived in that repo) -- pinned to a specific sha-<hex> tag from this repo's image, not tracking any floating tag. Getting a merged/released change here actually live requires, in order:

1. Cut the release as above (base image only, per docs/RELEASING.md).

2. Manually trigger agent-comms-approvals' deploy.yml via workflow_dispatch, passing base_image = the new sha-<hex> tag from step 1. This builds and pushes the derived board image to dev ECR, then promotes it to prod ECR, in one dispatch (no gate between dev and prod in this step -- see that repo's own workflow comments). The base image's commit must be at or after agent-comms-mcp commit 5e9a375 (AGENT_TOKEN_VERIFIERS) or the dispatch fails closed (TECH-5689).

3. Open a Terraform PR against redesignhealth/rh-data-platform bumping the pinned image tag/floor SHA in infrastructure/environments/{dev,prod}/reclaw_comms.tf's tfvars (mirroring PR #8407's pattern for that same file). Get it through CI/Argus.

4. Merge -- dev's Terraform apply runs automatically on push to main. Prod's apply does not -- it's workflow_dispatch-only with dry_run=false, run manually.

Full step-by-step walkthrough, including why deploying the plain base image alone already changes live message-holding behavior (before any of the wiring above lands): agent-comms-approvals' docs/TECH-5389-ROLLOUT-RUNBOOK.md (written for the initial TECH-5389 rollout specifically -- re-verify its "current state" table before trusting it, it's an explicit point-in-time snapshot, not a live dashboard -- but §2-§5's mechanics are the general, still-current pattern for any future change here too).

Local / self-hosted (Docker Compose):

cp .env.example .env   # fill in real values
docker compose up --build

Required environment variables (see .env.example):

Optional environment variables:

entrypoint.sh runs alembic upgrade head automatically on every container start, so migrations apply before the server accepts traffic.

Minting agent-jwt tokens

agent-comms-mcp-mint-token (installed alongside the other console scripts) mints agent-jwt Bearer tokens against AGENT_JWT_SECRET:

# Human-owned agent
agent-comms-mcp-mint-token --sub ea-agent-svc --scopes "comms:read comms:write" \
  --owner-email alice@example.com

# Self-owned agent (no human principal)
agent-comms-mcp-mint-token --sub notifier-bot --scopes comms:write --self-owned

# A bot submitting proposals via POST /proposals (TECH-5872) -- MUST be
# human-owned via --owner-email, NOT --self-owned. What --self-owned does
# depends on whether the bot is already registered:
#   - UNregistered self-owned bot: owner_sub is unresolvable, so
#     POST /proposals returns 422.
#   - Already-registered self-owned bot: POST /proposals returns 200 and
#     silently stores the proposal with owner_sub = bot_sub -- but it is
#     then permanently invisible via GET /proposals/pending, which scopes
#     to the CALLER's own Okta sub, not to a bot's.
# Either way, a proposal-submitting bot's owner_sub must resolve to an
# Okta identity that can actually call GET /proposals/pending.
agent-comms-mcp-mint-token --sub linear-progress-bot \
  --scopes comms:proposals:write --owner-email alice@example.com

--owner-email/--self-owned are mutually exclusive and one is required: skipping this choice is exactly how an agent silently becomes self-owned instead of human-owned, which later makes anything requiring that human's approval unsatisfiable until the agent is re-minted with the correct owner. See docs/TECH-5389-APPROVAL-PIPELINE.md §15 for the full rationale.

License

MIT. See LICENSE.