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

Goes well beyond the annotations by disclosing async job semantics, the polling contract, the ~24 hour expiry on upstream result URLs, and the 2-credit cost charged by mcp-credit-gateway before forwarding. These are exactly the operational traits an agent needs and none are derivable from readOnlyHint/openWorldHint/idempotentHint alone.

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?

Five tight sentences, front-loaded with the resource scope, then the async contract, then the expiry and cost caveats in descending order of importance. No sentence is redundant.

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?

With no output schema, the description still explains what comes back (job_id when still running, result URLs otherwise) and the expiry risk on those URLs. Combined with the cost note and size limits, an agent has everything needed to call and follow up 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 earns above that by explaining the cross-parameter contract (job_id resumes polling instead of creating a new billable job) and reinforcing the wait_seconds and image size limits. It stops short of clarifying the interaction between 'to'/'from' and a resumed job_id, which would be the remaining ambiguity.

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 ('Translate text inside 1-10 images') plus the input medium (public URLs) and format constraints, which cleanly separates it from translate_text, translate_document, and ocr_image. An agent can identify the tool without opening the 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 strong operational guidance for the async flow: wait up to wait_seconds, poll by re-calling with the same job_id, and that polling does not start a new job. It does not explicitly name the sibling alternative (e.g., translate_text for plain text, translate_document for files), so the when-to-use-vs-alternative dimension is implied rather than stated.

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