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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It thoroughly covers: the direction encoded in the phrase, refusal of unsupported phrases with a listing, idempotency, permission requirements, and the effect on get_issue returning 'links'. This exceeds what the schema alone conveys.

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 detailed but each sentence adds value. It is front-loaded with a concrete example and logically organized: example, semantics, refusal, idempotency, permissions, and effect on get_issue. While longer than minimal, it is appropriately sized for the complexity of the tool and avoids redundancy.

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 tool with 3 required parameters and no output schema, the description is remarkably complete. It covers usage semantics, edge cases (unknown phrases), side effects (link appears on both issues), idempotency, permission requirements, and how to observe the result (get_issue returns 'links'). An agent has all necessary information to invoke it correctly.

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%, giving a baseline of 3, but the description adds significant semantic depth. It explains that 'type' is the phrase as spoken, clarifies the directionality via 'from' and 'to', and notes that arguments cannot disagree. It also gives examples and explains the refusal behavior, going well beyond the schema's field descriptions.

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 action 'Link two issues' with a concrete example using specific issue keys and a phrase. It differentiates from siblings like unlink_issues by describing the linking operation precisely, and the scope (two issues) is unambiguous.

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 on when to use the tool, including the idempotency behavior ('linking the same pair the same way again changes nothing') and the permission requirement to edit both issues. However, it does not explicitly name alternatives or contrast with tools like unlink_issues, so it stops short of full exclusion guidance.

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