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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds context the annotations cannot: results are limited to the 'latest finished' build per platform, and a multi-step human-in-the-loop prerequisite gates the call. It does not discuss what happens when no finished build exists, leaving one behavioral gap.

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?

What the tool does is front-loaded in the first sentence, and the prerequisite workflow follows in logical order. The final sentence ('Then record it in the project's Twinr section') is a useful bookend rather than filler, though the wording is slightly dense for four sentences.

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 only one parameter, an output schema that documents return values, and full annotation coverage, the description carries what it must: scope, prerequisite, and the human-approval rule. It stops short of describing edge cases such as an app with no finished build or link expiry, which would round it out.

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 is documented, so the baseline is 3. The description goes further by telling the agent where the app_id lives ('replit.md on Replit, otherwise AGENTS.md'), which is resolution guidance the schema only alludes to via 'Twinr section'.

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 opens with a specific verb-plus-resource statement: 'Get download links for the latest finished Android and iOS build of one Twinr app.' It bounds scope by platform (Android/iOS), build state (finished), and cardinality (one app), so an agent can tell exactly what it returns without opening 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?

It states the precondition for calling (an application_id already recorded in the project's Twinr section) and gives an explicit alternative when that precondition fails: call list_apps, show the merchant every organization and app, and ask. It also names two prohibited behaviors ('Never choose one yourself', 'never infer it from the project's name or URL'), which is unusually strong when-not guidance.

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