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

Goes well beyond the readOnly/idempotent annotations by disclosing the visit-counting side effect, the 1-visit-per-owner-per-day cap, the X-Visit-Counted response header and why it exists, and the branch logic for destination selection. This is exactly the additional context structured fields cannot carry (note the mild tension with readOnlyHint=true, which the prose openly surfaces rather than hides).

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?

Four dense sentences, each carrying a distinct fact (action, dedup rule, header semantics, routing), and the core operation is front-loaded. The dash clause 'it is how the client knows without counting twice' is slightly belabored but not wasteful.

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 redirect tool with no output schema, the description covers destination resolution, the visit side effect, and the response header an agent needs to reason about. It stops short of describing the redirect response shape or failure modes (e.g., unknown id), leaving a small gap.

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% and the single `id` parameter is fully described in the schema, so the description correctly does not need to re-explain it. It adds no syntax or format detail beyond the schema, which is the expected baseline here.

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 action and target: a 302 redirect to the listing's origin, with the destination resolution spelled out (remote MCP server → repository, otherwise → /l/:id). Clearly distinct from get_listing/list_listings by the word 'hop'/redirect, but no sibling is named, so the agent must infer the contrast.

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 explains what happens mechanically but never says when to choose this over get_listing or list_listings, nor any prerequisite or exclusion. The 'use this to open/visit a listing' intent is only implied by the name, so genuine guidance is absent.

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