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

Annotations already declare readOnlyHint/idempotentHint, yet the description still adds substantial behavioral context: what a free result contains (metadata, Markdown body, source URLs, citation/bibtex), that premium results require a valid api_key, that a payment-required object is returned otherwise, and that unknown slugs yield did_you_mean suggestions. These are auth, success-shape and failure-mode disclosures an agent cannot derive from the annotations.

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?

Three tight sentences, front-loaded with the core action and followed by the return/auth/error variants. Every clause carries distinct information.

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 no output schema, the description carries the return-value burden and does so fully: free vs premium response shapes and the unknown-slug fallback. Nothing needed to call this 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 coverage is 100%, so both parameters are already documented. The description adds only that api_key gates premium content and that slug identifies a resource, which is marginal beyond the schema's own wording; baseline 3 applies.

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 and resource ('Fetch a ChangeGamer resource by slug'), which distinguishes it from siblings like get_article, list_resources and search_resources. An agent knows exactly what comes back without opening the 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?

Usage context is implied ('by slug' suggests a slug must come from search_resources or list_resources) but never stated explicitly. The description also names no alternative for when a slug is unknown beyond the did_you_mean hint; there is no explicit routing advice.

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