send_message

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

With no annotations, the description carries the full burden and does so: it discloses that confirm=False sends nothing and instead echoes back workspace, channel, text and attachments, explains the combined text+file comment behavior, and names the required OAuth scopes (files:write, im:write) with a pointer to check_access. That is unusually rich behavioral context for a mutation tool.

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 safety-critical constraint is front-loaded in the first line and the prose above the Args block adds real information. The Args list is long but earns its place given zero schema coverage; only minor redundancy remains between the prose and the parameter list.

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?

An output schema exists, so return values needn't be spelled out, and the description still explains what the preview payload contains. Combined with scope requirements, attachment semantics and threading, an agent has everything needed to call it correctly on the first try.

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% across 7 parameters, so the description must compensate and does — it documents accepted channel formats (C…/G…/D…, '#general', U…/W… for DMs), notes text is Slack mrkdwn and may be empty when file_path is set, and clarifies thread_ts, file_path and file_title defaults.

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 verb and resource ('Send a message to a channel') plus an immediate hard gate ('ONLY when confirm=True'). The confirm/preview mechanism makes it distinguishable from sibling draft_message without opening either schema.

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?

Explicit two-step protocol: call with confirm=False to preview, then repeat with confirm=True to post, and it states the preconditions for attachments. It does not, however, contrast itself with the sibling draft_message, which is the nearest alternative for composing without sending.

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