create_chat

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

No annotations, so the description carries the full burden. It usefully discloses the upsert-like behavior (Graph returns an existing chat) and the return shape, but says nothing about permissions, whether repeated calls create duplicate messages, or notification side effects.

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-loads the action and the no-lookup insight, then gives the return values and parameter hint. The parameter note is dense but every sentence contributes; no 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?

With an output schema present, the return-value mention is a bonus rather than a necessity, and the key ambiguity an agent would hit (whether to resolve the chat or the user first) is resolved. The remaining gap is message-format guidance for a mutation tool with no annotations.

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 0%, so the description must compensate. It thoroughly documents user_email (userPrincipalName, user id from get_user, alias caveat) but says nothing about the 'message' parameter's accepted format (plain text vs. HTML/markdown).

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 composite action: send a message in the 1:1 chat with a user, creating the chat if it doesn't exist. It explicitly distinguishes itself from list_chats (no lookup needed) and, by specifying '1:1', implicitly from create_group_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?

Gives clear usage context: 'no need to look it up with list_chats first' removes a common pre-step an agent would otherwise take. It does not state when NOT to use it or call out send_chat_message as the alternative for existing chats, so it stops short of full routing guidance.

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