Define the agent yaml

harbor.yaml is the single declarative file Harbor's runtime reads at boot. It's tiered by importance — REQUIRED at the top (the binary won't boot without it), then COMMON (the knobs you'll edit most), then ADVANCED (every other lever). Every absent key gets a documented default; the only fields you MUST set are identity + llm.

Pair this skill with harbor validate ./harbor.yaml — the validator is the loudest, most file:line-precise feedback you'll get on a yaml mistake. Run it after every edit.

REQUIRED — identity + llm

identity

The identity block configures JWT verification — the Runtime's authentication boundary. Every Protocol call carries a JWT; identity decides what algorithm to trust and where to fetch the public key.

identity:
  jwt_algorithms: [RS256]                      # allowlist: RS256/RS384/RS512/ES256/ES384/ES512
  issuer: https://issuer.example.com           # exact match against the JWT `iss` claim
  audience: my-agent                           # exact match against the JWT `aud` claim
  jwks_url: https://issuer.example.com/.well-known/jwks.json

For local dev, the scaffold drops placeholders — these pass harbor validate but reject any real token. harbor dev mints its own ephemeral signing key and bypasses the issuer/jwks_url path entirely (see run-the-dev-loop). For production, point issuer + jwks_url at your real IdP. HS256 / none are forbidden — the loader rejects them at boot.

llm

Pick exactly one provider block from the scaffolded examples. Bifrost (Harbor's LLM driver) speaks many providers under one wire surface; you swap providers by swapping the block, not by changing code.

llm:
  driver: bifrost                              # only driver shipped in V1.1
  provider: openrouter
  model: anthropic/claude-haiku-4.5
  api_key: env.OPENROUTER_API_KEY              # `env.NAME` resolves via os.Getenv
  timeout: 60s
  model_profiles:                              # effectively REQUIRED — one entry per model you use
    anthropic/claude-haiku-4.5:
      context_window_tokens: 200000            # the runtime uses this for context-window budgeting

model_profiles.<llm.model>.context_window_tokens is what the runtime consults for context-window budgeting. There is no silent fallback: a model with no matching model_profiles entry hard-fails the FIRST LLM call with ErrUnsupportedModel (fail-loudly — the error names the missing model_profiles[<model>] key). Set a profile for every model you reference. See wire-the-llm-provider.

COMMON — planner, memory, state, tools, skills, governance

planner

V1.1 ships one planner: react. The block tunes its budget and gives the planner extra domain guidance.

planner:
  max_steps: 12                                # how many reasoning turns before forced finalisation
  extra_guidance: |
    Voice/tone rules. Hard negatives. Safety notes.
    Operator-supplied; injected into the planner's system prompt.
  reasoning_replay: never                      # or `text` to round-trip the trace into the next turn
  token_budget: 0                              # 0 (default) = trajectory compression OFF; > 0 = once the
                                               # trajectory's token estimate exceeds it, the runtime
                                               # compacts step history into a summary (one compression
                                               # per run; needs the llm block)

memory

Multi-turn context. Default strategy is none (no memory across runs in a session); flip to rolling_summary for chatbot agents that need it.

memory:
  driver: sqlite                               # or `inmem` (dev default) / `postgres`
  dsn: ./my-agent-memory.sqlite                # MOVE outside the project dir to avoid the WAL trap
  strategy: rolling_summary                    # or `truncation` / `none`
  budget_tokens: 8000                          # max tokens replayed per turn

The WAL trap: dsn: ./... inside the project directory triggers harbor dev's fsnotify watcher and reboots the runtime in a loop. Default-drop the DSN at /tmp/harbor-validation/my-agent-memory.sqlite or ~/.harbor/my-agent-memory.sqlite. See run-the-dev-loop §3.

state

Durable run/task/session state. The default inmem driver is process-local — runs disappear on restart. Flip to SQLite for single-node persistence, Postgres for multi-replica.

state:
  driver: sqlite
  dsn: /tmp/harbor-validation/my-agent-state.sqlite   # WAL trap caveat applies

tools

Two sources: built_in (tools shipped in the harbor binary; opt-in by name) and mcp_servers (MCP southbound subprocesses Harbor spawns at boot).

tools:
  built_in:
    - clock.now
    - text.echo
  mcp_servers:
    - name: weather
      transport_mode: stdio                           # auto / sse / streamable_http / stdio
      command: [uvx, mcp-weather]                      # argv form; required for stdio
      headers: { Authorization: "Bearer ${env.WEATHER_TOKEN}" }   # HTTP transports; redacted as secrets
      keep_alive: 30s                                  # session-ping interval; 0 disables
      policy:                                          # optional per-server tool reliability defaults
        timeout_ms: 60000                              # per-attempt deadline (default 30000)
        max_attempts: 4                                # total attempts incl. the first

The planner discovers every MCP server's tools at boot — there's no per-server enable flag; listing the server registers its tools. Built-in tools live in the harbor binary — list clock.now to enable, omit to disable. MCP servers are external processes; see configure-memory-and-skills for the skill-vs-tool axis.

skills

Skills are token-savvy DB-backed playbooks the planner searches by name. Distinct from "operator skills" (the docs/skills/ directory you're reading right now) — these are runtime skills the planner consults during a reasoning turn.

skills:
  driver: localdb
  dsn: ./my-agent-skills.sqlite                # WAL trap caveat applies
  directory:                                   # optional — the per-turn <skills_context> browse window
    pinned: [triage-incident]                  # anchored first, declaration order
    max_entries: 10                            # 0/unset → planner.skills_context_max (default 5)
    selection: pinned_then_recent              # the one wired value (pinned_then_top is rejected: not yet wired)

Ingest skills with harbor skill import <path> and remove them with harbor skill rm <name> — both operate on this block's store.

governance

Per-identity cost ceilings + rate limits + max-token caps, keyed by tier.

Declared tiers are enforced. A populated identity_tiers block composes the enforcement subsystem at boot: the budget ceiling fails over-budget calls with ErrBudgetExceeded, the token bucket with ErrRateLimited, and the per-call cap with ErrMaxTokensExceeded — each emitting a matching governance.* event you can watch on the events stream. The same block drives the read-only governance.posture Protocol surface.

governance:
  default_tier: free
  identity_tiers:
    free:
      budget_ceiling_usd: 5.00                 # enforced cap per (tenant, user, session)
      max_tokens: 4096                         # per-call MaxTokens cap
      rate_limit:                              # token bucket per (identity, model)
        capacity: 100000
        refill_tokens: 50000
        refill_interval: 1h

Empty identity_tiers: {} = fully latent (the default).

ADVANCED — every other lever

The scaffold drops a commented summary of advanced defaults. The full reference is docs/CONFIG.md. The blocks you most often touch:

• server: bind_addr (default 127.0.0.1:8080 for harbor serve; harbor dev always binds :18080), allowed_origins (CORS allowlist for multi-process Console), shutdown_grace_period (drain timeout for hot reload).
• telemetry: log_format (json / text), log_level (debug / info / warn / error), service_name (OTel resource).
• artifacts: driver (inmem / fs / sqlite / postgres), heavy_output_threshold_bytes (the LLM-edge context-leak guard, default 32768 — see RFC §6.5).
• events: driver (inmem / durable); events power the Console's live streaming. Durable persistence is NOT selected on driver — set driver: durable and then pick the backing store with state_driver (sqlite / postgres) + state_dsn. With driver: durable and an empty state_driver the bus loudly degrades to best-effort in-memory (not durable across restart).
• sessions: idle_ttl (default 24h), hard_cap (default 720h / 30d), sweep_interval.
• pauseresume: max_park_duration (ceiling on how long a pause — HITL approval, tool OAuth — may stay parked before the runtime resumes it with the typed timeout decision and the run ends as a constraints-conflict; default 0 = never expire), sweep_interval (sweeper cadence, default 1m).
• tasks: driver (inprocess or durable). inprocess (default) keeps task/group/patch state in memory — a restart starts empty. durable persists those records through the StateStore so they survive a restart; on open it replays them and recovers any task left running by a crash to failed (code runtime_restarted). It reuses the runtime StateStore, so pair it with a durable state.driver (sqlite / postgres) for cross-process survival; selecting durable with no store wired fails loudly at boot.
• distributed: bus_driver (loopback or durable) + remote_driver (loopback only in V1.1; A2A wire is post-V1). loopback is in-process; durable persists every BusEnvelope through the StateStore and projects it onto the local event bus, with a poller for cross-instance fan-out + restart-replay (StateStore-backed — Postgres-as-queue on a shared Postgres store; tune with bus_poll_interval). NATS / Redis Streams remain future drivers.

Validation — the loud loop

harbor validate ./harbor.yaml

Failure modes the validator catches:

• Required field missing — llm.driver, llm.provider, llm.model, identity.issuer, etc.
• Type mismatches — memory.budget_tokens: "8000" (string instead of int).
• Enum violations — memory.strategy: "summary" (not one of none / truncation / rolling_summary).
• Bound violations — governance.identity_tiers.free.budget_ceiling_usd: -1 (negative).
• Cross-field constraints — memory.driver: sqlite without memory.dsn.

Every error carries the file:line of the offending key. Fix one, re-run, repeat until clean.

Common failure modes

• harbor validate says unknown field "X". Either a typo (check indentation — YAML is whitespace-sensitive) or the field belongs in a different block. Check docs/CONFIG.md for the canonical block.
• harbor dev boots but every Protocol call returns 401. Your identity block points at a real IdP but the JWKS isn't reachable. For local dev, use the dev-token flow (see run-the-dev-loop) — the issuer/jwks_url path is for production.
• harbor dev reboots in an infinite loop. SQLite WAL trap — dsn: inside the project directory. Move it outside.
• A model swap fails the first call with ErrUnsupportedModel. You forgot to add a model_profiles.<model>.context_window_tokens entry for the new model. There's no silent fallback — add the profile and the call succeeds.

See also

• scaffold-a-harbor-agent — drops the tiered yaml in the first place.
• wire-the-llm-provider — the full provider matrix + the mock vs real posture.
• configure-memory-and-skills — the memory strategies + runtime skill catalog in depth.
• validate-and-package — preflight before shipping.
• The full per-key reference: docs/CONFIG.md.