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

readOnlyHint=true already tells the agent this is a safe read, so the description earns credit for what it adds beyond that: exactly which fields come back and the crucial semantic note that the public scan URL (urlinks.me/{alias}/foo) is the one used by QR codes and shareable links. That domain detail is not derivable from the schema. It stops short of stating ordering or total-count behavior.

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?

Three short sentences, front-loaded with the resource, then the return shape, then the one non-obvious semantic detail. Every sentence carries information, though the final two sentences overlap somewhat in re-explaining the public URL.

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 two-parameter read tool with no output schema, the description compensates by describing the returned fields and the meaning of the public URL. What is missing is minor: result ordering, whether the response includes a total count, and how this differs from search_links at scale.

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%: limit (default 100, max 500) and offset are fully documented in the schema, and the description adds nothing about them. Baseline 3 applies since the schema carries the parameter burden.

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 gives a specific verb and resource ("List all your shortlinks") and goes further to enumerate the returned fields: slugs, destination URLs, descriptions, and the public scan URL. It is clear what the tool does, but it never names or rules out the sibling search_links, which is the obvious alternative for anything other than a full enumeration.

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?

"List all your shortlinks" implies the use case is unfiltered enumeration, which implicitly distinguishes it from search_links. However, there is no explicit when-to-use statement, no exclusion (e.g. "use search_links when filtering"), and no mention of pagination behavior when the collection is large.

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