search_emails

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

Annotations already declare readOnlyHint=true and idempotentHint=true, establishing a safe read operation. The description adds valuable behavioral context by stating it 'Returns envelope summaries newest first, with pagination', clarifying output shape and ordering that are not in annotations. This goes beyond the structured data 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, front-loaded with the core action, and every phrase earns its place. It avoids redundancy with the schema and annotations while covering return format and pagination.

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?

The description is complete enough for a search tool with 10 parameters and an output schema: it states purpose, return type (envelope summaries), ordering (newest first), and pagination. However, it does not explicitly mention relationships to sibling tools like 'list_emails' or 'get_email' when more context might be needed, so slightly below perfect completeness.

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 description coverage is 100%, so the baseline is 3. The description lists high-level search dimensions (text, sender, recipient, etc.) that map to parameters, but each parameter already has a descriptive schema comment. The description does not add significant new meaning beyond what the schema already provides.

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 uses a specific verb 'Search' with a clear resource ('messages in a folder') and enumerates the search dimensions (text, sender, recipient, subject, date range, unread state). It distinguishes itself from siblings like 'list_emails' and 'get_email' by focusing on filtered search that returns envelope summaries.

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 implies usage for filtered email searches but does not explicitly state when to choose this over siblings like 'list_emails' or 'get_email'. No exclusions or alternative tool names are given, so the context is only implicit.

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