google_ads_performance_report

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 states 'Read-only; no mutation,' which is a key behavioral trait. However, it does not mention error conditions, authentication requirements, or rate limits. The read-only disclosure is sufficient for a typical read operation.

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?

The description is concise at about 4-5 sentences. It front-loads the main purpose, then details return shape, read-only nature, and usage guidance with sibling references. No superfluous words; each sentence adds value.

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?

The tool has 3 optional parameters and no output schema. The description explains the return shape (one row per campaign with specific fields) and provides sufficient context for an agent to understand its role among many sibling tools. Missing error conditions are acceptable for a well-documented API.

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% with descriptions for all three parameters. The description adds value by explaining the customer_id fallback to credentials, campaign_id optional for all campaigns, and period default with usage guidance on window selection. This supplements the schema well.

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?

The description clearly states the tool aggregates campaign-level performance metrics for a Google Ads account over a reporting window. It specifies the return shape and lists metrics. It distinguishes from siblings by naming specific alternatives for per-ad, network splits, search terms, and conversions.

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?

The description explicitly says when to use it ('campaign-level totals') and when not, referencing four sibling tools for alternative granularities. It also provides guidance on period choice (short window for recent changes, long window for trends).

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