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

The description adds significant value beyond annotations: it confirms this is a WRITE (mutating) operation (annotations are readOnlyHint=false, so no contradiction), explicitly calls out idempotency (matching idempotentHint=true), explains what 'clearing' means (null or empty string), and discloses plan/auth requirements that annotations don't cover. No annotation contradictions found.

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 sentences, no fluff. The first sentence nails purpose and scope; the second covers idempotency and plan requirements. Every word 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 simple 2-parameter tool with no output schema, the description perfectly covers the operation, idempotency, auth/plan requirements, and parameter nuances. No gaps given the context signals (high schema coverage, no nested objects, no enums).

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% (both parameters documented in schema), so baseline is 3. The description adds value by clarifying that note supports null/empty string for clearing, and that tracked_keyword_id must be the internal `id` not `keyword_id` from other tools. This contextual advice elevates it above pure schema repetition.

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 explicitly states this is a WRITE tool that 'sets or clears the note on a tracked keyword', using specific verbs (sets, clears) and identifying the resource (tracked keyword, note). It distinguishes itself from siblings like sonar_track_keywords (which adds keywords) and sonar_star_keyword (which stars keywords) by focusing exclusively on the note field.

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 clearly states when to use this tool (to set or clear a note with motivation/hypothesis), provides context about idempotency (re-sending same note is no-op), and specifies prerequisites (Indie plan, trial counts, write-scope API key). It doesn't explicitly say when NOT to use it, but the narrow scope and condition clarity make this a minor gap.

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