get_stream

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

Annotations declare readOnlyHint=true and openWorldHint=true, so the agent already knows it is a safe read operation. The description adds value by specifying that it retrieves a 'message stream' by 'permalink', which clarifies the exact resource and lookup key. It does not contradict annotations, and the behavioral profile is largely covered by annotations plus the simple retrieval nature.

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: 'Retrieve one message stream by permalink.' It is appropriately sized, front-loaded with the action, and contains no extraneous words. Every word contributes to understanding the tool's purpose.

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?

This is a simple retrieval tool with one parameteraisle and no output schema. The description, combined with the annotations and full schema coverage, provides sufficient context for an agent to select and invoke the tool correctly. The only minor gap is that it does not describe what the response looks like, but the lack of an output schema and the simplicity of retrieval make this acceptable.

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%, meaning the schema already defines 'permalink' as 'Stream permalink'. The description does not add additional detail about the permalink format or required syntax beyond what the schema provides. With full schema coverage, the baseline of 3 is appropriate; the description does not need to elaborate further.

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 verb 'Retrieve' and the resource 'message stream by permalink'. It is specific enough to distinguish this from list_streams (which lists streams), though it does not explicitly differentiate it from get_email or other get_* siblings. The purpose is clear and not a tautology.

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 that this tool retrieves a single stream by permalink, which suggests using it when you have a permalink and need the full stream details. However, it does not explicitly state when to use this over list_streams or mention any alternatives. The guidance is implied but not explicit.

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