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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds genuinely new behavior: it searches titles AND full text, and each match returns the passage that best answers the query rather than a bare link — that result-shape detail is not in the annotations or schema.

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?

Front-loaded with the action and corpus, then the ranking/return behavior, then the sibling routing rule. The long enumeration of resource kinds is informative but is the bulkiest part; it could have leaned on the type enum instead of restating all eleven values.

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?

With no output schema, the description must convey what comes back, and it does: matches plus the best-answering passage. The content coverage (own measurements vs. guides) is useful scope information. It stops short of describing match fields or ordering, a minor gap for a simple search tool.

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. The description nevertheless adds value by mapping its enumerated content kinds onto the type enum and by framing the query as a question or topic whose best-matching passage is returned, which clarifies result semantics beyond the schema's example strings.

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 (search) and a specific corpus (everything WarmInboxes publishes), then enumerates the resource kinds so the agent knows exactly what is indexed. It also explicitly contrasts with the sibling read_resource, which returns a whole page, so the two are distinguishable without opening either 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?

The closing sentence gives a clear routing rule: search with find_resources, fetch a full page with read_resource. That covers the main alternative, but nearby siblings such as cold_email_writing_resources and find_tools are not addressed, so an agent could still hesitate between those and this tool.

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