gmail_reindex_semantic

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

Annotations already declare readOnlyHint and idempotent, so the description's 'read-only toward Gmail' is consistent reinforcement plus added context (privacy: embeddings run locally, nothing leaves the machine; data source limited to recent inbox threads). It adds meaningful non-schema behavior, though it omits duration/cost of a rebuild.

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?

Three short sentences: what it does, where data goes, and safety posture. Front-loaded with the action; nothing wasted.

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 zero-param, idempotent, local operation with no output schema, the description covers action, data scope, privacy, and Gmail-side safety. Minor gap: no guidance on when to trigger a rebuild or expected latency.

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?

Zero parameters, so baseline is 4. The description usefully clarifies that the corpus is 'recent inbox threads' since no parameter controls scope — that is exactly the kind of info a param-less tool needs.

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?

Specific verb (rebuilds) + resource (local semantic search index) + scope (recent inbox threads). Clearly distinguishable from siblings like gmail_semantic_search (which queries) and gmail_search_messages (Gmail-side search).

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?

Implies usage context ('from recent inbox threads') but never states when to run this versus using gmail_semantic_search, nor how often/when a rebuild is warranted. No sibling is named. Usage is inferable but not guided.

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