check_purpose_permittedVerify whether a requested purpose is allowed under source terms, supporting wildcard and hierarchical matching.
Check if a purpose is permitted under source terms. Supports wildcards (research:*) and hierarchical matching.
| Name | Required | Description | Default |
|---|---|---|---|
| purpose | Yes | Purpose to check (e.g. research:academic, training:model) | |
| allowedPurposes | Yes | Purposes allowed by the source terms |
Changes observed during successful MCP inspections.
v4.0.0Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Input schema / additionalPropertiesRemoved value: -falsev2.8.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered by structured data. The description adds genuine behavioral context beyond that: wildcard support ('research:*') and hierarchical matching, which tells the agent how the comparison actually behaves. It stops short of describing return/error semantics.
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, no filler, with the core predicate stated first and the matching behavior second. Every sentence earns its place.
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 two-parameter, read-only predicate tool with fully documented parameters and annotations covering the safety profile, the description is nearly sufficient. The one gap is that no output schema exists, so the return shape (presumably a boolean plus rationale) is left for the agent to guess.
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%, so baseline is 3, and the schema already gives examples for 'purpose'. The description adds matching semantics (wildcards, hierarchical matching) that govern how the two string inputs are compared, which is meaning the schema alone does not convey.
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: 'Check if a purpose is permitted under source terms', which is clear and actionable. It does not, however, differentiate itself from near-name siblings such as check_usage_permitted or check_combination_permitted, so an agent lacks an explicit disambiguation signal.
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 phrase 'under source terms' implies the scenario (validating a requested purpose against a rights/terms list), so usage is inferable. But there is no explicit when-to-use, no when-not-to-use, and no routing to the many sibling 'check_*' tools that an agent must choose between.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.