Read PDF metadata

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

Annotations already declare readOnlyHint and idempotentHint; description reinforces read-only nature, details return object structure, and explains behavior for encrypted files without password. No contradiction.

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 sentences with clear structure: purpose, return format, read-only emphasis, use cases with alternatives, and edge case handling. No unnecessary words.

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?

Covers tool purpose, return data, read-only behavior, usage guidance with alternatives, and edge cases. Output schema exists; description complements it fully. No gaps.

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%, but description adds context: explains include_page_details reduces response size and how password parameter affects output for encrypted files. Adds value beyond schema.

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?

Description clearly states 'Read a single PDF's document-level metadata' with specific verb and resource, distinguishes from sibling tools like analyze_pdf and extract_text, and lists exact return fields.

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 states when to use ('inspect what a PDF is before deciding how to process it') and when not to (use analyze_pdf for structural validation, extract_text for actual text). Also covers edge case of encrypted files.

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