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

The readOnlyHint annotation already communicates that this is a safe read operation. The description adds that it reads 'valid' IDs, hinting at filtering or validation, but doesn't explain what 'valid' means or what the return format is. With annotation coverage, a 3 is appropriate—it adds some context but no operational details like output shape or caching.

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?

A single, efficient sentence that front-loads the purpose. No unnecessary words.

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 zero-parameter read-only tool, the description is minimally adequate but lacks context about what the output looks like, how it relates to sibling list tools, or any usage conditions. The absence of an output schema means the description could help by describing return values, but it does not.

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?

Parameter count is 0, so the baseline is 4. The description correctly indicates no input parameters are needed. No additional parameter semantics to provide.

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 uses a clear verb ('Read') and names the resource ('valid category and tag IDs'). It does not differentiate from siblings like list_categories or list_tags, leaving ambiguous whether it returns the same data. In fact it suggests taxonomy is distinct from those list operations, but does not clarify the relationship.

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?

No guidance on when to use this tool versus alternatives. With siblings list_categories and list_tags, an agent might reasonably call those instead. The description does not state when this tool is appropriate or how it differs from those siblings.

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