slack_conversations_open

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

With readOnlyHint=false and openWorldHint=true already declaring this as an external mutation, the description earns credit for supplying what they don't: the idempotent no-duplicate guarantee and the return shape ('the channel id ... comes back at channel.id'), which matters because there is no output schema. Auth scopes and rate limits are not mentioned.

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?

Three short sentences, front-loaded with what the tool creates and followed by the two facts that affect calling it (return path, idempotency). No filler or restatement of the title.

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 four-parameter mutation with no output schema, the description covers the essentials: what it creates, the idempotent behavior, and where the resulting id appears, which compensates for the missing output schema. It omits permission/scope requirements and what a group conversation means at the API level, so it is not fully complete.

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 four parameters (users, channel, returnIm, preventCreation) are already documented in the schema; the baseline is 3. The description's 'one person, or a group message with up to eight' merely restates the users parameter mapping that the schema already gives, adding no syntax or format detail.

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 (open) and resource (direct or group message conversation) and immediately scopes it with 'with one person, or a group message with up to eight'. It also ties itself to the downstream sibling slack_chat_post_message, so an agent can place it correctly among the Slack conversation tools without opening a 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?

Usage context is clear: this is the step you take before chat_post_message, and the idempotency note ('opening the same conversation twice returns the existing one') tells the agent it is safe to call without dedup logic of its own. It stops short of explicit when-not guidance, e.g. that a conversation already known by id can be used directly without calling open.

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