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

Goes far beyond the annotations by documenting a concrete failure mode (BILLING_INACTIVE, MONTHLY_CAP_REACHED), the response field to expect (tellHuman), and the correct agent behavior (relay to human, don't silently continue read-only). This is exactly the behavioral context annotations cannot convey.

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?

Purpose is front-loaded in one short sentence, then the billing paragraph. The billing block is long but earns its place by changing agent behavior; a slight trim of the emphatic repetition would improve it.

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 2-param write tool with no output schema, the description covers purpose, usage motivation, and the critical error path with the exact field name returned. Only missing pieces are body content expectations and confirmation of what a success response looks like.

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 50%: `issue` is documented inline, `body` is not. The description's guidance to 'record what you did and why' gives soft content guidance for body, but no format/length constraints. Baseline 3 given partial schema coverage.

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?

Opens with a specific verb+resource: 'Add a comment to an issue.' Unambiguous about what the tool creates, though it never explicitly distinguishes itself from siblings like list_comments or retract_comment.

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 'comments + activity are shared memory — record what you did and why' line implies the intended usage pattern, but there is no explicit when-to-use/when-not guidance and no named alternative for reading or deleting comments (list_comments, retract_comment exist as siblings).

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