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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered; the description adds genuinely non-obvious behavior beyond that — link immutability, the side effect that reading a short link registers a visit and keeps it alive, and a prompt-injection warning that the markdown is untrusted. The only gap is that it never states the response shape for failure cases (e.g. what happens on an expired or malformed link).

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 compact sentences, front-loaded with the core action, then the sibling routing, the immutability/workflow rule, the visit side effect, and the security note. No filler and nothing repeated from the schema.

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 single-parameter read tool with no output schema, the description covers everything an agent needs: what comes back (markdown), how to edit (render_markdown), the immutability constraint, the visit side effect on short links, and the trust boundary. Nothing material 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% for the single required `url` parameter, and the schema already names both accepted link forms, so the description mostly restates it. The extra context it provides about short links (visit counting) is behavioral rather than param-level guidance, so baseline 3 is appropriate.

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 and resource ("Get the markdown behind a jotbins link") and enumerates the two supported link forms (jotbins.com/d and surl.jotbins.com), so the agent knows exactly what it retrieves. It also implicitly differentiates from the sibling render_markdown by assigning that tool the write/create path.

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?

Gives explicit use cases ("read, quote or edit it") and an explicit alternative with its condition: to edit, change the markdown and call render_markdown for a new link. It also flags the caveat that reading a short link counts as a visit and keeps it alive, which affects when an agent might hesitate to call it.

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