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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the read-only, external-fetch profile is covered structurally. The description adds the content of the feed (author, date, body, comment count), but does not disclose pagination behavior, completeness limits, or ordering. With annotations carrying the safety profile and an output schema present, a 3 is appropriate.

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?

Two tightly written sentences: the scoping and output content come first, the sibling routing second. Every clause earns its place with no redundancy.

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?

With an output schema present, the description need not explain return values, and the 100%-covered parameters plus read-only annotations cover the rest. Sibling routing and input identification are fully specified, so nothing required to invoke it correctly is missing.

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 description coverage is 100%, so both creator and slug are already documented in the schema with URL-segment examples. The description only restates that these are path segments, adding no syntax or format detail beyond the schema. Baseline 3 is correct 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?

The description names a specific verb (Fetch) and resource (one Kickstarter campaign's complete updates feed), and pins the identity inputs to the creator and slug path segments. An agent can distinguish it from kickstarter_project, kickstarter_comments, and kickstarter_discover without opening any schema.

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?

It explicitly routes the agent: use kickstarter_project for campaign details, kickstarter_comments for discussion, and kickstarter_discover to find projects. This names the alternatives and the conditions that select them, 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.