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

The description adds significant behavioral context beyond annotations: it explains the warming mechanism with retryAfterMs, that no credits are charged, and the confirmation_required error for out-of-scope focus. This complements the annotations (readOnlyHint=false, openWorldHint=true) without contradiction.

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 concise (5 sentences) and front-loaded with the primary action. Every sentence provides necessary information: what it does, when to use, behavioral notes (warming, errors, credits). No filler or 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?

The description covers key aspects: purpose, usage signals, parameter behavior, errors, and cost. With an output schema present, return values need no explanation. Minor gap: does not explicitly state that expansion adds sources/stories to the project, but it's implied from 'broadens coverage' and 'fetches them inline'.

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?

The input schema already has high coverage (100% with descriptions). The description adds value by explaining usage nuances: 'Omit to broaden the whole project' for focus, and the automatic addition of out-of-scope confirmed foci for addAsCriteria. This enhances understanding 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 tool broadens a project's coverage by expanding relevance criteria, finding sources, and fetching them inline. It specifies conditions for use (topic_unavailable, no_stories, low-coverage signal), distinguishing it from siblings like betterpost_add_source which add individual sources.

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 when to apply the tool (on topic_unavailable, no_stories, or low-coverage signal). It also provides context for out-of-scope focus requiring confirmedByUser. However, it does not explicitly mention when to use alternatives, though the conditions are clear.

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