Full-Text Search (Local Index)

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

Annotations already declare readOnlyHint=true. Description adds rich behavioral context: BM25 ranking, FTS5 syntax details, performance comparison, and prerequisite to rebuild index. 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?

Two sentences, front-loaded with verb+resource, each sentence carries essential information with no 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 4 parameters, output schema exists, and no nested objects, the description covers all critical aspects: purpose, syntax, usage conditions, and prerequisite actions. No gaps remain.

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 has 100% coverage with descriptions. Description adds significant value: explains FTS5 syntax (phrases, boolean, prefix, column filters), gives examples (subject:invoice from:alice), and specifies limit range (1–200, default 20).

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?

Title and first sentence clearly state 'BM25-ranked keyword search over the locally-indexed mail corpus'. Distinguishes from sibling 'search_emails' by noting it's 'Faster and smarter'.

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 states when to use (requires local index) and when not (call fts_rebuild if empty), and names alternative (search_emails).

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