Merge at least two PDFs in fileIds order. Costs 1 credit per started 10 total input pages, max 100 input pages. Output expires after 10 minutes. Rewriting can invalidate digital signatures.
| Name | Required | Description | Default |
|---|---|---|---|
| pages | No | ||
| title | No | ||
| author | No | ||
| degrees | No | ||
| fileIds | Yes | ||
| subject | No | ||
| requestId | Yes | Unique operation ID, reused for retries. 8–80 letters, digits, underscores or hyphens. Successful retries are not charged again for 90 days. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description goes well beyond the annotations by disclosing a precise cost model ('1 credit per started 10 total input pages'), the 100-page maximum, the 10-minute output expiration, and the side effect that rewriting can invalidate digital signatures. These are meaningful operational behaviors an agent needs to know.
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 three sentences, front-loaded with the core action, then follows with high-value constraints and warnings. Every sentence contributes operational information without filler.
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 seven parameters, no output schema, and low schema coverage, the description is not complete enough. It does not explain how to retrieve the merged output beyond saying it expires, nor does it describe the roles of pages, degrees, title, author, and subject. It also says 'at least two PDFs' while the schema allows minItems 1 for fileIds, which could confuse an agent.
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?
With only 14% schema description coverage, the description needed to compensate, but it only clarifies fileIds order and indirectly references page limits. Parameters like pages, degrees, title, author, and subject receive no semantic explanation in either the description or the schema. This is a significant gap for correct invocation.
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 opens with 'Merge at least two PDFs in fileIds order,' a specific verb and resource with an explicit ordering constraint. It clearly differentiates this tool from siblings like pdf_split and pdf_rotate, and the naming plus description leave no ambiguity about its function.
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 implies usage for combining PDFs and states prerequisites (at least two PDFs, the meaning of fileIds order). However, it does not explicitly discuss when to prefer this tool over alternatives such as office_to_pdf or pdf_extract, nor does it provide exclusions or alternative routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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