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

Beyond the readOnlyHint and destructiveHint annotations, the description discloses the return format ('Returns matching messages with the chat they came from') and a usage constraint ('Provide at least one of query, from_sender, since, until'). This adds valuable behavioral context without contradicting the annotations.

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?

Two sentences, front-loaded with the primary action and scope, then use-case, return, and a requirement. Every sentence adds value with no redundancy or 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?

For a read-only search tool with an output schema and fully documented parameters, the description covers the essential aspects: what it searches, when to use it, what it returns, and a required filter constraint. No critical gaps remain for the agent to invoke it 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?

Schema coverage is 100% with each parameter already described. The description reinforces the parameter roles ('text, sender name, and/or date range') and adds an explicit requirement that at least one filter be provided, which is not present in the schema. This supplements the schema meaningfully.

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 a specific action ('Searches') on a specific resource ('Microsoft Teams chat and direct-message history'), and emphasizes the cross-chat scope ('all conversations at once'). This distinguishes it from sibling tools like teams_read_chat_messages that operate on a single chat.

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?

Provides clear guidance on when to use this tool: 'to find where something was discussed in Teams without knowing which chat.' This implies the alternative use of chat-specific reads when the chat is known, though it does not explicitly name alternative tools.

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