Contract-gated verification

Policy failures return a structured 428 result with tool_out_of_scope, policy_violation_argument, or policy_violation_sequence, plus amendment guidance in _meta.amendment.

Published contract versions carry three policy fields:

• task_summary: the intended scope the reviewer agent must preserve.
• argument_guards: per-tool field rules such as max, allowlist, pattern, and required.
• sequence_graph: allowed next-tool transitions per trace.

You can inspect all three on the hosted MCP Contracts tab.

• Each footprint_trace_id locks to one contract version. Switching contracts mid-trace returns trace_contract_conflict.
• Any proxy tool outside the locked manifest (including reads) returns tool_out_of_scope.
• Scope changes should go through request_contract_amendment, not a new contract proposal in the same trace.

On a policy block, an agent can call request_contract_amendment with an explanation and proposed guard or sequence changes. The reviewer agent returns one of:

• approve: PreMan publishes a new contract version immediately with actor reviewer_agent.
• reject: the call stays blocked and the rationale is returned.
• error: the reviewer failed or timed out, and the call stays blocked (fail closed).

When human approval is configured for the contract binding, reviewer publishes are flagged for operator follow-up and can be reverted from the Contracts tab.

1. Before proxy tools/call, propose and publish a contract via preman_propose_verification_contract / preman_publish_verification_contract (include reads in tool_manifest).
2. Read policy block details from the tool-call _meta.violations.
3. Submit request_contract_amendment with footprint_trace_id, an explanation, and proposed changes.
4. Poll get_amendment_status; on approval, retry the original tool call.
5. When the task is done, call preman_complete_task with optional expected_outcomes to trigger Tier 2 verification.

Each tool call can carry a trace id (_footprint_trace_id in arguments). PreMan correlates invocations, action events, and verification runs into an ordered timeline at GET /verification/traces/{trace_id}/footprints. Use it to debug retries, see which contract version ran, and review failed checks across iterations.

Verification results on tool calls include _meta.verification with tier, trust level, verdict, iteration counters, and retry hints when checks fail.

Read plans are trialed at publish time in shape-only mode: PreMan checks tool existence, template resolution, response parseability, and locator validity. Missing objects are warnings, not hard failures.