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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), so the description earns credit for adding real behavior: a 366-day maximum window and the rule that platforms are never summed because each holds its own ad account's currency. Those are non-obvious constraints that change how an agent interprets and requests the data.

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-loads the one-line summary before expanding into the tab reference, window, and metric list. The metric enumeration is long but each item is informative; no filler sentences.

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 reporting tool with full schema coverage and no output schema, the description covers grain (per platform per day), metric set, currency semantics, and the date-range cap. Return shape specifics (sorting, zero-rows, missing platforms) are the only notable omissions.

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 since/until and source_ad_account_id are already documented with formats. The description adds the range constraint (366 days max) and the meaning of the source account as the bridging origin, but nothing beyond that; the baseline of 3 is appropriate when the schema does the heavy lifting.

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 outcome: 'Copied creatives' results per platform, day by day', and pins the scope to creatives bridged from one Meta ad account, which distinguishes it from generic reporting siblings. It never names the closest alternatives (get_bridge_stats, get_daily_breakdown, get_platform_daily_breakdown), so differentiation is left to inference.

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 through 'The Bridge's Daily tab' and the Meta-source framing, so an agent can guess this is the bridged-copy daily view rather than the campaign/account daily views. There is no explicit when-to-use/when-not statement or pointer to a sibling for the non-bridged case.

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