get_stream_messages

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description carries a lower burden. It adds the useful detail that messages can be retrieved from the beginning or end of the stream ('first or last N'). However, it does not describe ordering guarantees, pagination, performance characteristics, or any other behavioral traits beyond what the schema and annotations already convey.

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 description is a single, concise sentence that is front-loaded with the core action and resource. It contains no filler, repeated information, or unnecessary context, making it highly efficient.

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 simple read-only tool with a full output schema and annotations, the description covers the essential functionality. It specifies the main behavioral variant (first vs. last N) but does not elaborate on return value structure or edge cases; however, the output schema handles return details. The description is adequate given the annotations and schema richness.

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 for parameters is 100%, with all 5 parameters having clear descriptions. The tool description itself does not add any parameter-level information beyond what the schema provides, so the baseline 3 is appropriate.

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?

The description clearly states the action ('Get') and the resource ('messages from a stream'), and specifies the scope ('first or last N'). This distinguishes it from sibling tools like get_stream_schema (which retrieves schemas) and get_stream_time_range (which retrieves time ranges), both of which are about metadata rather than message content.

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?

The description implies usage: if you need to inspect messages from a stream, use this tool. However, it does not explicitly mention when to prefer this over alternatives like execute_query or list_streams, nor does it provide any exclusions or prerequisites. The guidance is implicit rather than explicit.

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