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

Adds real behavioral context beyond the annotations: it is a mutation (consistent with readOnlyHint=false) but FREE (no credits), and it documents the Google disavow-file format constraint. Cost information is not derivable from annotations, though idempotency and openWorldHint are left for the annotations to carry.

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?

Front-loaded with the action, then the cost/mutation warning, then the entryType semantics. It is one long sentence with a parenthetical aside, so slightly denser than ideal, but every clause carries information.

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 5-parameter mutation tool with no output schema and full annotation coverage, the description covers cost, mutation status and format semantics. It omits what the call returns or confirms, but the annotations and schema absorb most remaining ambiguity.

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%, so the baseline is 3, but the description goes further by explaining why 'value' must be a bare host for 'domain' and why no subpath form exists per Google's format. This clarifies the semantics of a required parameter beyond the enum text.

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?

States a specific verb and resource: 'mark one URL or domain for disavowal' within 'Disavow file management'. An agent can immediately separate this from list_disavow_entries, remove_disavow_entry and export_disavow_file without opening a schema.

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?

Gives explicit selection guidance between the two entryType modes — 'url' for exactly that page, 'domain' for the domain and its subdomains, plus the caveat that subpaths cannot be disavowed. It does not, however, say when to reach for this tool versus add/remove/list siblings in the disavow family.

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