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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds a useful behavioral trait beyond annotations: 'Secrets are never returned.' This tells the agent that sensitive data is excluded from the response, which is valuable context not available in the structured fields.

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 two short sentences with zero wasted words. The core action and the important caveat are front-loaded. 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 simple fetch-by-id tool with one parameter and annotations covering read-only and idempotent behavior, the description is adequate. It states the action and the secret caveat. It doesn't detail return format or error handling, but those are not critical for a straightforward fetch operation. It is complete enough for an agent to call correctly.

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?

The schema documents the 'id' parameter with a description ('Channel id.') and coverage is 100%. The tool description does not add any additional meaning about the parameter, so the baseline score of 3 is appropriate per the rubric.

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 states a specific verb ('Fetch'), a specific resource ('a single notification channel'), and the identifier ('by id'). It clearly distinguishes from siblings like list_channels, which lists multiple channels, and test_channel, which performs a different operation.

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: when you have a specific channel id and need a single channel. However, it does not explicitly mention when not to use it or name alternatives. The purpose is clear enough that an agent can infer the correct use case without further guidance.

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