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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered structurally. The description adds the upstream endpoint mapping, useful context, but says nothing about auth requirements, 404/not-found behavior, or what the response contains. With annotations carrying the safety burden, this is an acceptable but thin addition.

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?

Two short sentences, zero waste, with the core action front-loaded before the API detail. Nothing is padded or redundant.

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 one-parameter read tool with full schema coverage, an existing readOnlyHint, and no output schema, the description supplies everything needed to select and invoke it. Only minor gaps remain, such as error behavior on an invalid or missing id.

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% and the single 'id' parameter is documented in the schema as an integer listing id, so the schema does the work. The description adds nothing beyond naming the id parameter, which is the correct baseline.

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 ('a single channel listing'), and explicitly scopes it to one record retrieved by id, which cleanly separates it from the sibling list_listings. The appended API route (GET /v2/listings/{id}) reinforces exactly what it does.

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?

Usage is only implied: 'by id' signals it is for point lookups rather than enumeration, and the existence of list_listings as a sibling makes the split inferable. There is no explicit when-to-use/when-not statement or named alternative, so this is minimum-viable guidance.

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