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

With no annotations provided, the description must disclose behavioral traits on its own. It only mentions 'using directree's structured facts,' which is vague and does not clarify whether the operation is read-only, what the output format is, or how errors are handled. Since 'compare' implies read-only but is not stated, transparency is limited.

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 a single, succinct sentence that communicates the action and scope without unnecessary words. No redundant details or filler.

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?

Given the simplicity of the tool (one parameter, no output schema), the description is adequate but not thorough. It lacks information about return values, error behavior, or any prerequisites. More context on what 'structured facts' looks like would improve completeness.

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 input schema already fully describes the single 'slugs' parameter with min/max constraints and a descriptive comment. The description adds no new semantic information about the parameter beyond what the schema provides, so the baseline of 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?

The description clearly states the tool's function: comparing 2-4 tools side by side. This distinguishes it from sibling tools like get_tool (single tool retrieval) and search_tools (searching). The verb 'Compare' and resource 'tools' are specific.

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 provides clear context that this tool is for comparing a specific set of tools (between 2 and 4). However, it does not explicitly mention when to prefer it over alternatives or list exclusions. The purpose is clear enough that an agent would use it when needing a side-by-side comparison.

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