Search messages

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

Annotations already establish read-only, non-destructive behavior. The description adds useful behavioral context beyond that: it uses Microsoft Graph $search, searches specific message fields, and returns compact summaries rather than full messages.

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 a single focused sentence with a small example list and a final note on output format. Every part earns its place, and the key behavioral distinction is front-loaded.

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 simple search tool with one required parameter, read-only annotations, and no output schema, the description is mostly complete. It could more fully describe the returned summary fields, but 'compact summaries' plus the schema and examples provide enough guidance for correct invocation.

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?

The schema already documents both parameters well, so the baseline is 3. The description adds extra meaning by giving concrete query examples such as 'from:alice@contoso.com' and 'subject:release', which illustrate the field-scoped syntax beyond the schema's simple examples.

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 states a specific action ('Full-text search') and resource ('the mailbox'), and scopes it to subject, body, sender, and recipients. This clearly distinguishes it from sibling tools like list_messages, which would be a plain listing rather than a 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?

The description makes clear this is the search-oriented tool and even shows query syntax with examples. It does not explicitly say 'do not use this to list all messages' or name alternatives, but the context is strong enough for an agent to select it appropriately.

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