add_evidence

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

No annotations are present, so the description carries the full burden. It does disclose that the operation is mutating and adds a meaningful semantic boundary: evidence does not affect control status. However, it omits other behavioral details a fully transparent unannotated mutation tool might include, such as idempotency, duplicate handling, or permission requirements.

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 action and target, and the second adds essential semantic caveats. There is no filler or redundancy.

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?

For a moderate-complexity mutation tool with an output schema and a well-covered input schema, the description provides the key contextual facts: what it attaches, that it is mutating, and that it does not affect control status. It could mention behavior like replacing vs. appending evidence, but overall it is sufficiently complete for an agent to use it appropriately.

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 83%, so the baseline is 3. The description's mention of 'doc, link, or artifact reference' loosely maps to the `type` parameter, but the schema already documents each parameter's meaning and defaults, so the description adds little beyond that.

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 opens with a specific verb and resource: 'Attach an auxiliary evidence item (doc, link, or artifact reference) to a control.' It clearly scopes what the tool does and distinguishes itself from the sibling tool remove_evidence by framing attachment vs. detachment.

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 explicitly states when this tool is appropriate and when it is not: evidence is contextual metadata only, does not count toward implementation status, and only assertions prove controls. It also directs users to remove_evidence for detaching an item, giving a clear alternative.

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