security_fetch_package_licence

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

Annotations declare readOnly, no destruction, idempotent. Description repeats and adds context: 'Read-only. No side effects. Idempotent.', plus caching (1-hour) and data source (deps.dev). 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?

Well-structured: main action first, then safety, parameters, usage, alternatives, source/cache, feedback. Every sentence adds necessary information without redundancy.

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 the tool's simplicity and presence of output schema, the description covers all needed aspects: purpose, parameters, return format, usage context, alternatives, caching, and feedback. No gaps.

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 coverage is 100% with basic descriptions. The description adds concrete examples (e.g., 'flask', '2.3.0') and lists valid ecosystems explicitly, providing value 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?

The description clearly states the action ('Fetch the SPDX licence identifier') and the resource ('open source package version'). It distinguishes from the sibling tool security_fetch_package_vulnerabilities by noting the different purpose (licence compatibility vs security issues).

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?

Explicitly tells when to use ('verify licence compatibility before including a dependency') and when not to ('use security_fetch_package_vulnerabilities instead'). Also includes a feedback mechanism for agent gaps.

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