create-planner-task-message

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

Annotations already indicate readOnlyHint false and destructiveHint true, so the burden on the description is reduced. The description explains the effect (posts a message teammates will see) and adds deployment constraints (beta, delegated accounts, global cloud). However, it does not mention that this is considered destructive or that confirmation might be required (the confirm parameter is only in the schema). It adds some context but not fully beyond 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?

The description is dense but every sentence earns its place: purpose, modernization context, body structure example, and critical constraints (beta, environment, no ETag). It is front-loaded with the core action and uses a tip for guidance. No fluff or repetition.

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?

Given there is no output schema, the description covers the input structure, provides an example, and lists constraints. It doesn't explain the return value, but for a create operation that is often standard. It omits mention of the confirm parameter, but the schema describes it. Overall, the description is sufficient for an agent to call it correctly in most scenarios.

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 high (80%), but the description adds a concrete body example: { content: 'plain text or sanitized HTML', mentions?: [...] } and clarifies that mentions are optional. It also warns that plannerTaskId must be passed under that name, not as 'id'. This goes beyond the schema descriptions and provides practical usage guidance.

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 opens with 'Create a new plannerTaskChatMessage on a plannerTask' – a specific verb and resource. It further distinguishes this from the legacy conversationThreadId comment, clarifying exactly what object is being created. The name itself is unambiguous, and the description reinforces the purpose without ambiguity.

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 tip clearly states this is the modern 'task chat' versus the legacy comment thread, and notes that Microsoft is retiring classic comments, so this is the supported path. It also indicates the body structure and mentions. It doesn't explicitly name alternative tools like list-planner-task-messages or delete-planner-task-message, but the context implies when to use it (for posting) vs. those. The beta and environment constraints are also noted, which help an agent decide suitability.

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