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

readOnlyHint=true already tells the agent this is a safe, non-mutating read. The description reinforces scope (active vs archived, date-range and alias/tag filtering) but adds little beyond what the schema's type enum and filter params already say; the endpoint path is the only genuinely new context.

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?

A single front-loaded sentence captures the core purpose plus filter scope, followed by the endpoint for reference. Nothing is wasted, though the trailing GET path is marginally redundant for an agent that already has the name and params.

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 zero-required, four-parameter counting tool with a 100%-covered schema and safety covered by annotations, the definition is sufficient. The only mild gap is that with no output schema it doesn't explicitly state the return is a scalar count, though that is inferable from the name.

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%, so all four parameters (from, to, type, search) are already fully documented in the schema. The description restates the filtering capabilities but adds no syntax or format detail beyond it, so the baseline 3 applies.

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 (count/how many) and resource (short links) with explicit scope (active, archived, all account links). An agent can distinguish this from sibling tinyurl_list_links purely by intent — this returns a number, not records.

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?

It says the count can be 'optionally within a creation date range or filtered by alias or tag,' which implies when the filters apply, but it never names an alternative (e.g., use list_links to retrieve the links themselves) or a when-not condition. Usage is implied rather than directed.

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