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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds one genuinely useful nuance with 'Attempt' — signalling best-effort recovery that may fail — but says nothing about what happens on failure, whether the original is preserved, or how the recovered output is returned.

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?

A single seven-word sentence with the key qualifier ('damaged or corrupted') front-loaded and nothing redundant. It is terse to the point of under-specification, but not padded.

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 one-parameter tool with rich annotations and no output schema, the description covers the core action but leaves an agent guessing at the return shape (repaired PDF bytes? base64? a status flag?) and failure semantics. 'Attempt' is the only hint about outcome behavior.

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 0% for the single parameter 'fileBase64', and the description never mentions it. The name hints at base64-encoded PDF bytes, but constraints (size limits, encoding expectations, whether the whole file must be supplied) are undocumented in both places.

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 ('recover') and resource ('damaged or corrupted PDF'), which is unambiguous and distinct from every sibling (all of which are transform/compress/extract tools). It stops short of explicitly contrasting with any sibling, but none overlaps, so the purpose is clear.

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?

There is no guidance on when to use this versus, say, re-generating a PDF or using pdf_flatten, no mention of prerequisites (e.g., must be a PDF that fails to open), and no note on whether the input is expected to be readable. The agent must infer the trigger condition entirely.

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