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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds real context beyond them: the authentication requirement and the shape of what comes back (aggregates, per-day breakdown, ranked lists). It says nothing about the plan-based day cap or pagination/limits, which would have pushed this higher.

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 sentences: the first front-loads the returned data, the second carries the prerequisite and usage examples. No filler, no repetition of the title, and the reader knows the scope and the trigger by the end of the second sentence.

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?

With no output schema, the description takes on the job of describing return content, and it does so thoroughly (totals, daily breakdown, top links/countries/referrers/devices). Auth requirements and the account-level scope are also stated, so an agent has everything needed to call it correctly.

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%, so both parameters (days, links) are fully documented in the schema including defaults and plan limits. The description alludes to 'by day' and 'the busiest links', loosely mapping to the two params but adding no syntax or constraint detail. Baseline 3 applies when the schema does the work.

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 (get) and resource (account stats), then enumerates exactly what data is returned: clicks and QR scans, totals, by day, busiest links, top countries/referrers/devices. The scope phrase 'across every link in the user's Snip account' cleanly separates it from get_link_stats without needing the schema.

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 concrete triggering questions ('how are my links doing', 'which link got the most scans this week') and the prerequisite that the user must be signed in. It does not name get_link_stats or state when the per-link tool is preferable, so routing between the two is left partly to inference.

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