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

With readOnlyHint=true already declaring the safety profile, the description adds useful behavioral context beyond annotations: it is a credential-verification / discovery call, and it reveals the underlying endpoint. It does not cover rate limits or return format, but the annotation carries the safety burden.

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 purpose, then usage, then endpoint. No filler, every sentence 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?

For a zero-param, read-only tool with no output schema, the description covers purpose, usage, and roughly what is returned (settings and channel types). Slightly more detail on the returned shape could help, but nothing essential to correct invocation is missing.

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?

Zero parameters, so there is no parameter semantics to document; baseline is 4. The description correctly implies a no-argument app-scoped call.

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 (Fetch) and resource (the Stream app's settings and configured channel types), which is clearly distinct from the resource-scoped siblings like stream_get_channel and stream_get_message. An agent can identify the app-level metadata role without opening a schema. It also pins the exact endpoint (GET /api/v2/app).

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 tells the agent when to use it: 'Good first call to confirm credentials and discover available channel types.' That is concrete usage context rather than inference. It stops short of naming an alternative tool or stating when not to use it, so it is not a 5.

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