Extract plain text

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

Even though annotations already mark readOnlyHint=true and idempotentHint=true, the description adds further behavioral context. It states the tool is 'read-only' and describes the return JSON structure ({text, page_count} and 'page' when a specific page is requested). It also mentions that out-of-range page indices return an error. This goes beyond the annotations without contradicting them.

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?

The description is exceptionally concise: three sentences. The first sentence states purpose, the second describes return format and readonly nature, and the third provides usage alternatives. No filler or redundant information. Every sentence earns its place, and the structure is front-loaded with the core action.

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?

Given the tool's simplicity (3 parameters, 1 required, simple output schema), the description is complete. It covers return format, error behavior (out-of-range page), and usage context vs. siblings. The output schema exists but the description still explains return fields. All necessary information for correct invocation is present.

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 100%, so the baseline is 3. The description adds some extra context beyond the schema: it mentions that 'page' parameter accepts a 0-based index and that out-of-range values return an error (already partly in schema but reinforced). It also implies that 'password' is for encrypted PDFs. However, it does not detail each parameter extensively; the schema already does that well. The added value justifies one point above baseline.

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?

The description clearly states the tool's purpose: 'Extract the raw, unformatted text of a PDF as a single string.' It identifies the verb (extract), resource (raw text of PDF), and output format (a single string in JSON). The title 'Extract plain text' reinforces this. It also distinguishes from siblings by specifying when to use convert_pdf (for Markdown structure) and extract_entities (for coordinates and font). This is specific and differentiates among 12 sibling tools.

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?

The description explicitly says 'Use this when you want the plain reading text.' and provides clear alternatives: 'if you need Markdown structure or chunking for LLM/RAG pipelines use convert_pdf; if you need each text run with its on-page coordinates and font use extract_entities.' This gives concrete when-to-use and when-not-to-use guidance, making it easy for the agent to select the correct tool.

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