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

Annotations already declare readOnly, non-destructive, idempotent, and closed-world, so safety is covered. The description adds genuinely useful non-schema behavior: it returns locations and counts but never the hidden text, and it carries a per-PDF price of 0.01 USDC. It does not cover response shape or failure modes on malformed PDFs, which keeps this at solid-but-not-rich.

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 the core capability, then scope exclusions, then return/price facts — all high-value. The trailing 'MCP tool: `check_redactions`' restates the name and earns no place, a minor inefficiency in an otherwise tight definition.

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 single-input read-only tool with no output schema, the description covers what is detected, what is deliberately excluded, what is returned (locations and counts, not hidden text), and the cost. Nothing an agent needs to invoke it correctly is missing.

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?

Only one parameter (file_base64) and schema coverage is 100%, so the schema already carries the encoding requirement and the 4 MiB cap. The description adds nothing about the input beyond what the schema states, making the baseline of 3 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 concrete verb and resource: finds black boxes drawn over text in a PDF and reports where the underlying text is still selectable, plus unapplied redaction annotations. The scoping clause ('checks text only') separates it from sibling metadata/image scanning tools without needing their schemas.

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?

Explicitly defines the boundary: text only, not images, metadata, or earlier revisions, which tells the agent when this tool is the wrong choice and implies the metadata/provenance siblings instead. It stops short of naming a specific alternative tool to call for those cases.

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