read_attachment_image

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

With no annotations, the description carries full burden. It discloses internal behavior: resolves presigned URL, fetches bytes, returns native MCP image content. It also documents failure conditions: raises for non-image MIME types and exceeding the 5 MB cap. This is thorough and non-contradictory.

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?

Four sentences, front-loaded with the main action. Every sentence adds distinct value: purpose, use case/benefit, operational detail, and constraints/errors. No filler or 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?

Adequate for a read tool with no annotations or output schema: explains return type (MCP image content), size limit, and error triggers. The sibling context (get_attachment_url) is referenced, and the tool's role in the attachment lifecycle is clear.

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 description coverage is 100%, so baseline is 3. The description does not add parameter-level detail beyond the schema's own descriptions of issue_id and attachment_id, but no compensation is needed.

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 opens with a specific verb+resource: 'Fetch an image attachment and return it as MCP image content.' This clearly differentiates it from siblings like get_attachment_url (returns URL), list_attachments (lists metadata), and upload_attachment (writes).

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?

States the intended use case ('Lets vision-capable models look at a screenshot/photo on a task directly') and explicitly contrasts with receiving a URL and downloading via shell tool. Also provides a when-not implicit by capping at 5 MB, implying use URL path for larger files.

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