list_sources

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

No annotations are provided, so the description carries the burden. It discloses authentication requirements and a specific limitation (handles not exposed). However, it does not mention read-only behavior, pagination behavior, rate limits, or error conditions. The tool is simple, so the transparency is adequate but not comprehensive.

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 two sentences with no redundancy. The first sentence conveys purpose and output fields; the second provides usage constraints and an alternative. Every sentence adds value, and it is front-loaded with the primary action.

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 simplicity of the tool (1 parameter, no output schema), the description covers the purpose, output fields, and a key usage constraint. However, it fails to explain the limit parameter and does not describe the return format or pagination, which are necessary for correct invocation.

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 0%, and the description does not mention the single parameter 'limit'. The purpose and behavior of 'limit' (likely pagination) are not explained anywhere. The description should have clarified this parameter's meaning and default behavior.

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 tool lists source catalog metadata and enumerates specific fields (type, language, country, audience, political lean). It also distinguishes from sibling coverage_stats by directing users to that tool for aggregate counts, but does not explicitly differentiate from get_breaking, get_feed, or search_news.

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 explicitly states the prerequisite (Standard-tier key or higher) and limitation (handles not exposed). It provides an alternative for a specific use case: 'Use coverage_stats() for public aggregate counts instead.' However, it lacks guidance on when to prefer this tool over other siblings like get_feed.

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