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

Annotations only supply readOnlyHint=true; the description adds the substantive behavioral facts the agent most needs: the tool returns a URL for the human to open, no fetching/reading of results happens on the Adbloop side, and it is available on every plan (no gating). Remaining gaps are edge behavior — e.g. what is returned if page_id is invalid or if both query and page_id are supplied.

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?

Three tight sentences, front-loaded with the use case, followed by selection modes and the critical no-fetch caveat. Nothing is repeated and no sentence is filler.

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 6-param, zero-required, no-output-schema tool the description covers the essentials: what it produces (a link), who consumes it (the user's browser), and that no data comes back. It does not explain how the optional filters interact with page_id mode, which is the one meaningful ambiguity left for an agent composing the call.

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 schema already documents query, country, page_id, active_only and exact_phrase. The description adds a mode framing (name/keyword vs exact Page ID) but largely restates what the schema says about page_id, and media_type — the only enum parameter — is undocumented in both schema and description. Baseline 3 fits.

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: builds a link to Meta's public Ad Library for a brand's ads. The framing ('Competitor research', 'The user opens the link in their browser; Adbloop does not fetch or read the results') cleanly separates it from sibling data-returning tools like get_creative_library or get_ad_preview, which an agent might otherwise confuse it with.

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 clear context ('Competitor research') and the two selection modes — search by name/keyword vs exact by Facebook Page ID. It also implicitly rules out expecting returned ad data. However, it never names an alternative tool for when the agent actually needs ad creative or insights, so the routing guidance stops short of explicit alternatives.

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