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

Beyond the readOnlyHint annotation, the description richly discloses behavior: how rating movement is computed relative to the first snapshot on/after `since`, the fallback to last-build trend when no snapshot covers the date, and the meaning of `basis`, `was`, and `compared_to`. It also transparently details pricing, capping, and plan inclusion.

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 dense but every sentence serves a purpose: core behavior, row-level semantics, fallback behavior, pricing, and cost estimation. The most important information is front-loaded, and formatting with backticks and dashes makes it scannable.

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?

Despite having no output schema, the description explains the key output fields (`was`, `compared_to`, `basis`), the fallback behavior, and the pricing model. An agent has enough information to call the tool correctly and interpret results. Schema covers `limit` and `context` adequately.

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?

The description adds meaningful semantics to the required `since` parameter by explaining that comparison is against the first scored snapshot on or after that date. This goes beyond the schema's bare 'YYYY-MM-DD.' It does not add much for `limit` or `context`, but those are adequately covered by schema defaults and descriptions.

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 identifies the tool's purpose: showing what changed in the catalog since a date, including providers added/updated and rating movement. It is specific about the resource and the date-based scope, but it does not explicitly differentiate this tool from related siblings like get_rating_history or find_rating_movers.

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 gives clear context for when to use the tool: when you need catalog changes and rating movement from a specific date. It also includes practical guidance like estimating price first, but it does not state when not to use it or name alternative tools.

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