Add Card External Link

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

Annotations only say readOnlyHint=false and idempotentHint=false; the description goes much further by disclosing that the POST response does not include card_id or external_link_id, and that these only appear in a later list response. This is a critical behavioral caveat that an agent cannot infer from the schema or annotations, and it is especially valuable because no output schema exists.

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 compact and well-structured: purpose first, then usage examples, then parameter constraints, then a high-value response caveat. Every sentence earns its place, and the note about missing response fields is front-loaded enough to be noticed.

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 write operation with no output schema, the description is remarkably complete. It covers what the tool does, when to use it, parameter constraints, return type, and the important response-shape limitation. No critical operational detail is missing for an agent to invoke and interpret this tool 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%, so the baseline is 3. The description adds meaning by reinforcing that url must be a valid URL with max length, that description is optional and length-limited, that cardId comes from another operation, and that verbosity affects the returned shape. This goes slightly beyond the schema by explaining intent and cross-tool provenance.

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 operation: 'Attach an external link (URL) to a card.' It names the exact resource (card), the action (attach), and gives concrete examples (Jira, GitHub PRs, design docs) that make it easy for an agent to recognize the tool's purpose and distinguish it from card editing or comment tools.

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 for when to use the tool: when linking a card to external resources like Jira or GitHub without cluttering the description. It also gives a helpful provenance hint ('cardId from kaiten_get_card'). It does not explicitly contrast with sibling tools like kaiten_update_card_external_link or kaiten_remove_card_external_link, but the use case is clear enough.

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