Add text or a typed signature

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

Annotations already declare the write/idempotent/non-destructive profile, so the description adds real value with the coordinate origin convention and the 'Latin characters only' limitation, a constraint not present in the schema or annotations. It does not restate the output-file/overwrite behavior, which the schema already covers.

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?

Two tight sentences with the action front-loaded, followed by the coordinate convention and the character limitation. No filler; every clause carries information.

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?

With an output schema, annotations, and 86% schema coverage, most structured detail is handled elsewhere. The description supplies purpose, coordinate convention, and the Latin-only constraint, leaving little an agent would need missing, though it says nothing about page-selection behavior beyond the schema.

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 high (86%), so the schema already documents x, y, size, pages, input and output. The description restates the x/y origin (schema already says points from left/bottom edge) and adds the Latin-only text constraint, so it adds marginal meaning over the structured fields – baseline 3 is 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 specific verb and resource (draw text on pages) and gives concrete use cases (typed signature, date, note). It is clear but does not explicitly differentiate itself from siblings like pdf_add_watermark or pdf_fill_form, which an agent might reasonably confuse it with.

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?

Examples of use cases imply when the tool is appropriate, but there is no explicit when-to-use/when-not guidance and no routing to alternatives such as pdf_add_watermark or pdf_fill_form. Usage is only inferred.

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