search_emails

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

With no annotations, the description carries the full burden and does so well: it discloses relevance-based ranking (not date-sorted), that received: filters are honored on AAD but IGNORED on the personal backend, automatic backend selection, and the return shape. These are non-obvious behavioral quirks an agent must know to call correctly.

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?

Purpose is front-loaded in the first clause and each sentence carries useful information (operators, account behavior, ranking, alternative). The single dense paragraph of intertwined caveats is slightly heavy but nearly all of it 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?

Despite having no output schema, the description explains the return format (compact JSON array of hits with message IDs usable by read_email), and it covers the query syntax and cross-account pitfalls. Nothing essential for correct invocation is missing.

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%, so the baseline is 3, but the description adds query semantics beyond the schema: additional operators (hasAttachment:true, body:, quoted phrases, AND/OR) and the critical caveat about date-operator behavior per backend. It does not, however, add anything for the limit parameter.

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?

States a specific verb and resource ('Full-text search across the user's ENTIRE mailbox') and scopes it explicitly (all folders, all years), which separates it from the folder-scoped list_emails sibling. An agent can identify the tool's job without opening the schema.

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?

Names the alternative ('use list_emails (folder-scoped) with since/until') and the exact condition that selects it (need for strict date filtering). It also clarifies cross-account behavior so the agent knows when results may be date-unreliable.

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