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

Annotations already mark this as readOnly and idempotent. The description adds useful behavioral context by specifying exactly what is returned (ID, title, method count) and clarifying that it does not return the list of endpoints, which exceeds the annotation-only information.

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 well-structured with headings, a summary up front, and bullet points for usage guidance. It is slightly longer than necessary, but each section adds value and it remains highly scannable.

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?

Since there is no output schema, the description compensates by explaining the return fields (ID, title, method count). It also provides clear usage context and sibling differentiation, making it complete for a simple read-only lookup tool.

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 the baseline is 3. The description adds valuable detail by specifying the id format as a '32-character MD5 hash ID', which is not present in the schema description, and reinforces that it is required.

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 'returns information about a single tag: its ID, title, and how many methods it contains.' It explicitly distinguishes itself from the sibling tool endpoint_by_tag, which lists endpoints within a tag.

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 includes a dedicated 'When to use' section with specific scenarios and a 'Do NOT use' instruction that names the alternative (endpoint_by_tag). This directly guides the agent on tool selection.

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