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

readOnlyHint=true already covers the safety profile, so the description adds real value by disclosing that a channel's account.id is the value to forward as channel_id, and by listing the underlying REST endpoints. This return-semantics context is useful given there is no output schema.

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?

Front-loads the purpose and channel enumeration, then the mode selection, then the output-forwarding detail, then the raw endpoint. Every sentence carries distinct, non-redundant information.

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 no-output-schema lookup tool, the description fully explains what is returned (channel types and the account.id to forward) and both invocation modes. Nothing an agent needs to call it correctly 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?

Schema coverage is 100%, so the baseline is 3, but the description adds the conditional logic the schema only hints at: case_id selects existing-case mode, and user_id applies only to the new-case mode (ignored with case_id). This clarifies the interaction between the two parameters beyond their individual schema descriptions.

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+resource ('List the channels') and enumerates the concrete channel types (MAIL, TWITTER, FACEBOOK, NOTE). It distinguishes itself from siblings by naming the two downstream tools (kayako_reply_to_case / kayako_create_case) that consume its output.

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 gives the two usage modes: pass case_id to list channels for replying to an existing case, or omit case_id (optionally with user_id) for a new case. It also tells the agent why it would call this tool — to obtain the channel_id needed by the reply/create tools.

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