assay

assay-pier-bridge

An isolated bridge between Assay and the Pier / mini-swe-agent execution stack. It has its own pyproject.toml and uv.lock so the bridge image’s dependencies are locked independently of Assay. The two sides do not import each other; they share only the wire contract (TrialRequest/TrialResult in src/assay_pier_bridge/protocol.py), across which Assay hands a sealed package built by assay.pier_packaging.

uv sync --group dev
uv run pytest

Container and trial-lifecycle tests skip when no Docker daemon is reachable.

Runtime identity

Three inputs, recorded as BridgeIdentity in protocol.py, must not change while trials are being served:

• mini-swe-agent — commit a83fcae82d2a08f0ee0c688f9d137b3566c097f8 (tag v2.4.6), pinned in pyproject.toml and resolved into uv.lock.
• Pier — see Pier revision.
• Bridge image digest — built from Dockerfile. A reference build (docker build -t assay-pier-bridge:test .) produced sha256:b3e07726d3e92731c1ac1f934d27457a6545a52660af484fd67fb092cf09dc3f. Rebuilding from the same lock reproduces the dependency set but not necessarily the same image ID, so the lock digest is the durable identity.

docker run --rm --network none assay-pier-bridge:test starts and exits 0, confirming the image never installs or resolves anything at trial time. tests/test_trial_lifecycle.py asserts the same thing for a running trial.

Pier revision

Pier is published on PyPI as datacurve-pier. pyproject.toml pins datacurve-pier==0.3.1 with hash pins in uv.lock; since Pier publishes no source commit, the version plus hashes is its identity.

pier_adapter.py maps a TrialRequest onto Pier’s TrialConfig and writes the task directory Pier’s loader expects; tests/test_pier_adapter.py checks both against the installed package. Two constraints follow from Pier’s schema:

• Upstream verification is disabled with the trial-level VerifierConfig.disable, which overrides anything a task declares.
• Pier’s network_mode supports only no-network and public. The agent therefore runs with no-network, and the model call is made by the bridge outside the sandbox (see below).

Limitation: Pier builds a per-task environment image through its own EnvironmentFactory, while this bridge reuses one locked image driven by container.py. These are not yet reconciled, so pier_adapter.py builds and validates the config and task directory but does not call Trial.create/Trial.run against a live backend.

Guarded model route

provider.py’s GuardedOpenRouterClient speaks only to POST https://openrouter.ai/api/v1/chat/completions on one pinned route (anthropic/claude-3-haiku via amazon-bedrock, mirroring assay.adapters.openrouter_policy.HAIKU_BEDROCK). It makes no retries, validates the response’s model, provider, and usage.cost, enforces the single-tool submission protocol, and fails closed on any unexpected field, route, or missing cost.

The trial container always runs with --network none, so the guarded call runs on the host: host_driver.GuardedCompletionTrialClient calls __main__.run_one_cell directly in the bridge process. DockerTrialClient in container.py is the sandbox lifecycle harness, covering mounts, uid, resource limits, and teardown.

Sealed package boundary

The bridge never reads a realization directory or repository root. It receives only instruction.md, the selected arm’s repository at /workspace (read-only), and the submission contract. /submission and /scratch are fresh, writable, per-trial mounts.