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

Annotations declare destructiveHint=true and idempotentHint=false, but the description adds far more: the reply cannot be recalled once queued, the audience is determined by the channel's default recipients setting, and a failed-in-transit call may still have queued the reply so the ticket must be checked before retrying. This is exactly the context an agent needs before an irreversible customer-facing write.

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 critical warning (WRITE, CUSTOMER-VISIBLE) and every sentence carries operational weight. It is somewhat dense and could be tightened, but there is 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 no output schema and only three simple params, the description covers what an agent must know: irreversibility, audience resolution, the approval gate, the alternative tool, and retry semantics after an ambiguous failure. Nothing essential is missing.

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%, so ticket_id, text and subject are already documented in the schema. The description adds semantic context about audience/recipients that the schema does not, but says nothing about subject usage or the 20000-char text limit, so the baseline 3 applies.

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?

Opens with a specific verb and resource ("send a reply on a ticket") and explicitly scopes it as WRITE, CUSTOMER-VISIBLE. It differentiates from the nearest sibling by routing internal notes to edesk_add_ticket_note, and mentions the underlying POST /messages with type Message.

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?

Names a hard precondition ("Only call this when the user has approved the exact text and audience"), an explicit alternative (edesk_add_ticket_note for internal notes), and a when-not case (use the eDesk reply box when recipients matter, since this API cannot choose them).

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