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

The annotations already cover the safety profile (read-only, idempotent, non-destructive, closed-world), so the description only needs to add context. It does that well by stating the answers come from 'the rules the API itself enforces' (authoritative, not generic legal commentary), that government source links are included, and that it reports what 'can't be marked yet'. It is silent on response shape and any rate limits, but that is a minor gap.

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 core purpose is front-loaded in the first clause, and the second sentence earns its place by establishing the authority of the data and the links. The sentence is long and slightly run-on, but it contains no padding.

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 read-only lookup with no output schema, the description does the necessary work: it explains what results will contain (required fields, label requirement, unsupported cases, government links). The deepfake handling is not described, but the schema documents it, so the definition is nearly complete.

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 coverage is 100%, with enum values and the markets format already documented, so this dimension has a baseline of 3. The description reinforces 'given markets' and the image/video/audio media types but does not mention the deepfake flag or add syntax beyond the schema.

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 names a specific resource (AI-labelling laws for given markets) and a specific output (what POST /v1/mark must send: required fields, whether a visible label is needed, what can't be marked). It never names a sibling tool, so an agent must infer on its own that this is distinct from read_doc, but the specificity of the resource makes the distinction reasonably clear.

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 phrase 'what a call to POST /v1/mark must send for them' gives a clear use context: consult this before constructing a mark request. The description does not list exclusions or explicitly point to read_doc for broader documentation, but the operational context is easy to infer.

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