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

Annotations already cover the read-only/idempotent profile, but the description adds substantial context beyond them: no credential is needed (pre-empting a common agent failure mode), the exact size caps and why they exist (bytes travel through context), and per-type return shapes (image, text, base64). This is exactly the operational detail 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?

Front-loaded with purpose and the no-credential warning, and every sentence carries a distinct fact (return types, size limits, proxy alternative, link attachments). It is on the long side — the credential warning and the size rationale could be tightened — but nothing is filler.

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?

No output schema exists, and the description compensates by describing all three possible return shapes and their caps. With one required parameter, read-only annotations, and the sibling routing spelled out, an agent has everything needed to call this correctly or know when not to.

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% and the single parameter is documented as 'Attachment id.', so the schema already does the work. The description adds only implicit context — that the id refers to an issue attachment obtainable via list_attachments — without adding syntax or format detail. Baseline 3 is appropriate.

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?

States a specific verb and resource — 'Read the CONTENT of a file attached to an issue' — and immediately distinguishes itself from metadata siblings by emphasizing CONTENT and 'ONE call'. An agent can tell it apart from get_attachment and save_attachment without opening any schema.

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?

Gives explicit routing: check `bytes` on list_attachments/get_attachment first if size matters, switch to `retasc mcp-proxy` for files over the limit, and fetch the URL yourself for link attachments. Each alternative has a stated condition that selects it.

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