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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the description only needs to add what annotations cannot. It does add real value by disclosing the export formats (markdown, csv, pdf) and the wrapped endpoint, but says nothing about what happens with an invalid/expired id or whether exports are generated on the fly versus cached.

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?

Two terse, front-loaded sentences with the read-only marker and primary resource first, followed by the routing hint and wrapped endpoint. The parenthetical endpoint note is mildly redundant with the URL already mentioned but remains useful.

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 no output schema, the description should describe the return more fully; it covers format options but not the structure of the JSON deep-dive payload or any metadata like run timestamps or status. Adequate for locating and fetching, thin for interpreting the result.

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 only 33%, so the description must carry weight. It clarifies `id` ('by id') and enumerates the export formats for `format`, which compensates partially, but the brandId defaulting behavior ('personal' / key owner's active brand) appears only in the schema, not the description.

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: 'One saved deep dive by id', plus the output forms (json or exported markdown/csv/pdf of the stored report). The word 'saved' implicitly separates it from ads_deep_dive_run and ads_deep_dive_quote, but it never names those siblings explicitly.

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?

Usage is implied by 'one saved deep dive by id' and the pointer to GET /api/v2/ads/deep-dives for listing recent runs, which tells the agent where to get ids. It gives no explicit guidance on when to prefer ads_deep_dive_run (generate new) or ads_deep_dive_compare, and no prerequisites or error conditions.

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