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

Annotations already declare a safe read, but the description adds substantial behavior beyond them: passwords are never returned (only passwordProtected), a deleted link surfaces as not found rather than as a tombstone, qrUrl is a payload address and not an image, and expiresAt/maxClicks/fallbackUrl are read-only duplicates of fields inside rules. These are exactly the non-obvious traits that would otherwise cause misinterpretation.

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?

Purpose and identifier are front-loaded in the first clause, and nearly every clause carries non-redundant information. The middle portion is a long run-on covering return fields, QR semantics, and read-only field duplication, which would scan better as separate sentences or a short list.

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 full burden of describing the response and does so field by field, including plan availability of clicks, the ruleLabels/manageUrl extras, and the relationship between top-level and nested rule fields. An agent can call this and interpret the result without further documentation.

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 parameter already carries an example, so the baseline is 3; the description earns an extra point by defining what a slug actually is ('the part of the short address after the last slash'), which resolves ambiguity about whether the full URL is acceptable.

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 one short link identified by its slug — and immediately enumerates what comes back (destination, status, addresses, clicks, rules, ruleLabels, manageUrl). It references create_link and update_link only as shape references, not as alternatives, so there is no explicit routing away from find_links or search_vault when the agent doesn't already have a slug.

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?

Usage is implied rather than stated: the tool requires a slug, so it is for the case where the identifier is already known, and the closing line 'A deleted link counts as not found' clarifies the failure mode. There is no explicit when-not or pointer to find_links for lookup-by-attribute, so the agent must infer the boundary.

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