set_attachment_as_card_picture

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

With no annotations, the description carries the full burden. It only states 'requires image file' but omits critical behaviors such as whether the action replaces existing thumbnails, is idempotent, requires specific permissions, or what errors occur for non-image attachments. This leaves the agent uncertain about side effects.

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 a single concise sentence that front-loads the key action and constraint. No extraneous words, but lacks any structural formatting (e.g., bullet points) to improve readability.

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?

Given that it is a mutation tool with no output schema or annotations, the description is incomplete. It omits the return value, potential errors, and any mention of side effects on the work item. For a tool that modifies data, more contextual completeness is expected.

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?

All three parameters are fully described in the schema (100% coverage), so the baseline is 3. The description adds the file requirement but does not provide additional context for the 'projectId' parameter or clarify parameter relationships beyond the schema.

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 ('set') and resource ('image attachment as card thumbnail') and includes a requirement ('requires image file'). However, it does not explicitly differentiate from sibling tools like 'upload_attachment' or 'delete_attachment'.

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 usage guidance is provided. The description only mentions a file type requirement but does not suggest when to use this tool versus alternatives (e.g., 'upload_attachment' to add an attachment, then this to set as thumbnail).

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