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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, yet the description adds substantial context: the cap of 10 newest reports, the report payload structure (parity/gaps/only-you features with share of inspected pages), the meaning of the insufficient_evidence state (<3 readable competitor pages or no owned page match), the meaning of an empty list, and the guarantee that it never fetches new pages.

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?

Purpose and usage are front-loaded and every sentence carries information, but the block is dense and run-on; the report-field enumeration and edge-case definitions could be broken out for faster scanning.

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?

There is no output schema, so the description correctly carries the return-value burden, describing report shape, the cap on results, and both degenerate outcomes (insufficient_evidence, empty list). An agent has everything needed to call it and interpret results.

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% and there is a single required project_id fully documented by the schema. The description adds no parameter-level detail, but with only one trivially documented parameter there is little the description could usefully contribute.

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 (Read) plus a precise resource (how competitor pages cited by AI answers differ from your own page, on topics they win). It is immediately distinguishable from sibling read_* tools, which cover traffic, visibility, crawlability, etc., rather than page-content comparison.

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 says when to use it ('before rewriting a page to compete') and names the prerequisite alternative ('Use read_visibility_sources to find the competing pages first'). Both the trigger and the routing to a sibling are stated, leaving nothing to inference.

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