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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description still adds real value: it discloses the return type (image content plus hashes), states that no OCR/interpretation/synthetic diagram is produced, and warns that no client path or URL is accepted — behavior an agent could not infer from annotations 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 dense sentences, front-loaded with what is returned and why it is useful, followed by input constraints and ROI semantics. Every sentence carries distinct information with no redundancy.

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?

An output schema exists, so return values need not be spelled out, and annotations carry the safety profile. The description supplies exactly the missing pieces: input shape constraints, coordinate system, and the negative scope (no OCR or interpretation). Nothing needed to invoke it correctly is absent.

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 only 25%, so the description must compensate, and it does: it defines doc_sha256 as a document hash, page as 1-based physical page, and region as normalized x/y/width/height on the rotation-applied page with a top-left origin, explicitly noting it is not a text bbox. Only max_dimension relies on the schema's own description.

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+resource: returns original-PDF pixels as an MCP image content item, with source and PNG hashes. This clearly distinguishes it from text-based siblings like get_page_blocks, get_figure_data, and get_datasheet_map, which the agent can infer deal with extracted text/data rather than raw pixels.

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?

'Useful for tables, graphs, pins and reference circuits that text extraction cannot represent' gives a clear condition for selecting this tool over text-extraction siblings. It stops short of explicitly naming an alternative tool or stating exclusions, so it is strong context rather than full when/when-not routing.

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