anvil_get_castFetch a cast — an Anvil PDF template — by its eid: title, version number, and whether it is a template. Use the returned eid as the cast_eid for anvil_fill_pdf. GraphQL query: cast.
| Name | Required | Description | Default |
|---|---|---|---|
| eid | Yes | The cast (PDF template) eid. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true. Description adds that it fetches specific fields and is used for filling PDFs, plus mentions the underlying GraphQL query. No contradictions.
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 concise sentences. First explains what the tool does, second gives usage guidance and technical note. No redundant 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?
Covers purpose, usage, parameter, and output fields. Does not mention error handling or edge cases, but for a simple fetch tool this is sufficient.
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 has 100% coverage for the single 'eid' parameter. Description adds meaning by explaining that the eid is used to retrieve the cast and then as input for fill_pdf, providing context beyond the schema.
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?
Clearly states it fetches a cast (PDF template) by eid and returns title, version, and template status. Distinguishes from siblings by linking to anvil_fill_pdf and specifying it's for PDF templates.
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?
Provides clear context for using the tool: fetch cast, then use eid for anvil_fill_pdf. Does not explicitly state when not to use or alternatives, but the purpose is well-defined.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.