Trace decision lineage

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, which lowers the burden. The description adds valuable non-obvious behavior: unresolved ids 'stay type-unknown' and canonical rule-lineage failures 'fail closed as protocol errors and are never returned as partial traces.' This is behavior an agent could not predict from annotations or schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded: the first sentence states the core purpose, the second covers behavioral guarantees and result types, and the third gives usage routing. Every sentence earns its place with no filler or redundant fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With a full output schema, rich annotations, and a single well-documented parameter, the description provides all necessary operational context: when to call, what ids are valid, what failure behavior looks like, and safety guarantees. Nothing needed for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The schema already documents that record_id is a stable proposal id or canonical decision id and that unknown ids produce trace_not_found. The description reinforces this but does not add meaningfully new parameter-level semantics beyond what the schema provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Return the deterministic lineage actually known for a proposal id or canonical decision id.' It explicitly distinguishes the tool from decision.get by naming it, and clarifies the scope of what is returned (lineage, not the record alone). The result_type detail further removes ambiguity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives direct, explicit routing guidance: 'Use decision.get for the record alone; use decision.trace when you need provenance, acceptance, rule, or declared-evidence lineage.' This tells an agent exactly when to choose this tool over a sibling, with no inference required.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.