lulu-print-mcp

Validate interior file

validate_interior_file

Starts validation of an interior PDF, optionally against a Lulu product SKU, and returns a record to poll for VALIDATED, NORMALIZED, or ERROR status.

Instructions

Start checking an interior PDF. Returns a validation record; poll get_interior_validation with its id until the status is VALIDATED, NORMALIZED or ERROR. With pod_package_id, Lulu also checks the file fits that product.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "source_url": "<source_url>"
    },
    "name": "validate_interior_file"
  }
}

Input Schema

Name	Required	Description	Default
`source_url`	Yes	Public URL Lulu downloads the file from. Basic-auth credentials in the URL are allowed.
`pod_package_id`	No	Lulu product SKU (pod_package_id): trim size, ink, quality, binding, paper and finish. Dotted format, e.g. '0600X0900.BW.STD.PB.060UW444.MXX' (6x9in black-and-white standard paperback, matte). Lulu still accepts the older 27-character format without dots until 1 February 2027. Build one with Lulu's pricing calculator: https://developers.lulu.com/price-calculator

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Nov 11, 2026

TDQS

A4.4/5.0

Behavior4/5

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

Annotations only declare the operation is not read-only, is open-world, non-idempotent and non-destructive. The description meaningfully adds the asynchronous lifecycle: it returns a record rather than a verdict, and the terminal states are enumerated. It does not say whether repeat calls spawn duplicate validations or how long validation takes, which is a notable gap for a non-idempotent tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the action, then the return contract and polling loop, then the optional parameter effect. 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.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the burden of explaining the return value and does so, including the id needed for polling and the terminal statuses. It does not explain failure modes such as how ERROR differs from a rejected request, which would be useful for an async job starter.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: supplying pod_package_id turns on an additional product-fit check rather than just formatting input. That tells the agent the parameter changes behavior, not merely the request payload.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The definition uses a specific verb and resource ("Start checking an interior PDF") and clearly separates itself from the sibling get_interior_validation, which it names as the polling endpoint. An agent can distinguish it from validate_cover_file purely from the resource name.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit workflow guidance: call this to start, then poll get_interior_validation with the returned id until status reaches VALIDATED, NORMALIZED or ERROR. It also explains the conditional value of pod_package_id. It stops short of stating exclusions, such as pointing cover files to validate_cover_file, but the resource naming makes that inferable.

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