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

No annotations are provided, so the description carries the full burden. It adds useful behavioral context ('live from Meta') and lists the returned fields, but it does not disclose error behavior, permission/access requirements, or explicitly confirm read-only behavior beyond the word 'fetch.'

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 sentences with the core purpose front-loaded, followed by a compact list of returned fields and a routing pointer. No filler, no redundant restatement of schema details.

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 simple two-parameter read tool with no output schema, it names the data source, the selector, the returned fields, and the alternative for SKUs. It only omits minor edge-case details such as not-found/error behavior, which are not essential for selecting and invoking the tool.

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. The description adds the FBID-vs-retailer_id distinction and the 'live from Meta' idea, but the input schema already documents numeric FBID, the non-SKU constraint, and ad_account_id's scoping/budget-check role.

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 ('Fetch'), resource ('full details of one catalog product'), and the exact lookup key (numeric Meta product ID / FBID). It also disambiguates this tool from the sibling search tool by explicitly contrasting FBID vs retailer_id/SKU.

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?

Explicitly tells the agent when not to use this tool: for a merchant SKU (retailer_id), use adsap_search_catalog_products with retailer_id instead. This gives a clear routing rule between two otherwise similar catalog tools.

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