defender_add_incident_comment

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

Annotations already signal a non-read, non-destructive operation, but the description adds critical behavioral detail: comments on merged incidents are written to the master incident and a redirectedFrom field communicates this redirection. This is the kind of hidden behavior an agent cannot infer from schema or annotations, and it directly affects where output will appear.

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, zero filler. The core action is front-loaded, and the important edge case about merged incidents is introduced with a conditional ('If the incident was merged...') that leads naturally to the redirectedFrom outcome. Every clause earns its place.

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 the tool's simplicity (two required string params, no output schema), the description sufficiently covers the action, the audience (analysts), and the only notable behavioral twist (merged incidents). A minor omission is the lack of mention of what the tool returns, but this is a low-complexity write operation where return value is rarely critical.

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%, with both incident_id and comment already documented. The description repeats the word 'comment' but adds no new parameter-level meaning beyond what the schema provides. Baseline 3 applies because the schema carries the full burden.

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 a specific verb and resource: 'Append a comment to an incident's comment thread,' which is unambiguous and differentiates from sibling tools like defender_add_alert_comment (which targets alerts, not incidents). The phrase 'a triage write' further clarifies the operational role, and the merged-incident behavior adds specificity without obscuring the core purpose.

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 appropriate use ('triage write,' 'visible to analysts') but does not explicitly state when to choose this tool over alternatives like defender_update_incident or defender_add_alert_comment. There is no mention of exclusions or conditions that would route an agent elsewhere, so context is present but left to inference.

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