update_slack_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 disclose the critical behavioral constraint (bot-authored messages only) plus replacement-not-append semantics. It is silent on failure modes for stale/deleted timestamps and Slack update rate limits, which leaves a real gap 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?

Front-loaded with the core action in the first clause, and each subsequent sentence carries distinct value (usage pattern, rationale, constraint). The illustrative status-marker example is slightly long but is the justification for the tool's existence.

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?

For a no-annotation mutation tool with no output schema, the description covers what to rewrite, how to obtain the identifier, the recommended pattern, and the authorization boundary. Missing only error/edge behavior (non-bot messages, expired timestamps).

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 all three parameters are already documented, including that ts comes from send_slack_message and that text is a full replacement. The description reinforces the ts provenance but adds no new parameter semantics beyond the schema baseline.

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 (rewrite) and resource (a message already posted), plus the key identifier (timestamp from send_slack_message). An agent can distinguish this from send_slack_message, send_slack_image, and slack_progress without opening any 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?

Gives an explicit workflow (post 'working on X', update as work moves, update once when done) and names the anti-pattern it replaces ('far better than posting a new message per step'). It also states the hard precondition: only messages this bot posted can be rewritten.

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