search_emails

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

The readOnlyHint annotation already signals no side effects. The description adds valuable behavioral context: it uses live IMAP (implying potential slowness or dependency on Bridge IMAP), applies some filters locally after fetch, and notes that the alternative works even when Bridge IMAP is unavailable. This goes beyond the bare annotation without contradicting it.

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 exactly two sentences, with the first sentence front-loading the action and resource, and the second providing decision-critical usage context. Every word earns its place with no wasteful filler.

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 tool's complexity (24 parameters, no output schema), the description covers purpose, usage context, and a clear alternative. While it doesn't describe return value shape or pagination, the schema's limit and fields parameters hint at those, and the readOnly annotation covers side effects. The description is sufficiently complete for an agent to invoke the tool correctly.

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?

All 24 parameters are already fully described in the schema (100% coverage), so the description doesn't need to explain them. It makes a brief connection to attachments and labels post-processing, but doesn't add significant meaning beyond the schema's detailed parameter descriptions. Baseline score is appropriate.

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's purpose: searching emails via live IMAP filters with optional local post-processing. It explicitly distinguishes itself from the sibling search_indexed_emails by naming it, making the tool's unique role obvious.

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 provides explicit usage guidance: use when real-time results are needed or when messages arrived after the last sync, and prefer search_indexed_emails when the local index is current due to speed and availability advantages. This is exactly what an agent needs to decide between the two tools.

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