Compress PDF

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

Annotations already declare openWorldHint=true and readOnlyHint=false. The description adds genuinely new behavioral facts beyond them: the file leaves the machine to be uploaded to conv2pdf, the call consumes one conversion from a quota, and password-protected inputs yield an unprotected result. It stops short of stating what is returned or how long the upload takes.

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 short sentences with no filler; the core purpose leads and the operational caveat (external upload, one conversion) follows. Nothing is redundant with the title or schema.

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 four-parameter conversion tool with no output schema, the definition covers what the operation does and its side effects (upload, quota, password stripped), which is enough to call it safely. It could still say what the caller receives back (e.g., confirmation plus the new file path) to close the last gap.

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% – quality levels, DPI mapping, default, password handling and output_path collision behavior are all documented in the schema. The description adds no parameter detail beyond that, so the baseline 3 applies.

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 (reduces the size) and resource (a PDF) plus the mechanism (lowering image resolution), which cleanly separates it from every sibling such as merge_pdfs, rotate_pdf, or extract_pdf_pages. An agent can pick it without opening a schema.

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?

Usage is only implied by the purpose statement; there is no explicit when-to-use/when-not rule and no routing to an alternative (e.g., a lossless-compression sibling, or a different tool when only page removal is wanted). The one contextual hint given is the quota cost of a conversion.

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