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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is fully covered. The description adds a data-integrity note ('Rankings are never paid') and names the returned fields, which is useful context, but says nothing about behavior for an unknown slug or how missing tools are signaled.

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 short sentences, front-loaded with the resource and key, then the payload contents. The closing trust claim about unpaid rankings is brief and earns its place as editorial context, though it is not strictly needed to invoke the tool.

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?

For a one-parameter read tool with full annotation coverage, the description carries the remaining burden by listing the returned fields in lieu of an output schema. Only the not-found behavior and slug format edge cases remain uncovered, which is a minor gap.

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 the single parameter is documented with an example ('cursor'), leaving nothing for the description to clarify. 'By slug' merely restates the schema, so the baseline of 3 is appropriate.

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 resource (a single StackPick tool) and its key (slug), and enumerates what comes back: category rank, score, website, last reviewed date. That clearly separates it from search_tools or get_best_tools, which return collections. It doesn't explicitly name which sibling to use instead when the slug is unknown, so it stops short of 5.

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 phrase 'One StackPick tool by slug' implies a single-record lookup rather than discovery, which is enough to infer it complements search_tools. However, there is no explicit statement of when to use this versus search_tools or get_best_tools, and no mention of what to do when the slug isn't known.

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