get_chat_messages

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

With no annotations, the description carries the burden. It discloses that the tool is read-only (no side effects), returns messages with author info including user.username, and emphasizes the prerequisite call pattern. It doesn't detail ordering or pagination, but the limit parameter covers some of that.

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 focused sentences, front-loaded with the core action. The second sentence provides crucial context about @mentions without unnecessary wording. Every word 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?

With no output schema, the description explains a key return field (user.username) and provides a usage sequence ('always call this BEFORE sending'). It lacks details about message ordering or full response structure, but for a two-parameter chat tool, this is sufficient for effective invocation.

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 coverage is 100% with descriptive parameter comments (room and limit have defaults/max), so the baseline is 3. The description adds minimal extra parameter semantics—it clarifies the purpose of the returned data but does not further explain room or limit behavior beyond the schema.

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?

Clearly states 'Read recent chat messages from a room' with a specific verb and resource. It distinguishes from siblings like send_chat_message by being the read counterpart, and the mention of returning author info for @mentions adds specificity.

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?

Explicitly instructs to call this tool BEFORE sending a message to know who to @mention, providing clear usage context and sequencing. This differentiates it from alternative tools and sets an explicit when-to-use directive.

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