Upload a release binary to App Distribution

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

With no annotations provided, the description carries the full burden and does disclose two non-obvious behaviors: it is an upsert ('creates a new release (or updates an existing one if the binary is identical)') and it returns a long-running Operation whose response eventually carries the release resource name. It omits any permission/auth or quota context, which is the remaining 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?

Three tight sentences, front-loaded with the action and artifact scope, then the behavioral caveat, then the workflow handoff. No filler or restatement of the title.

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 2-parameter tool with full schema documentation and no output schema, the description supplies what the structured fields cannot: accepted file formats, the upsert semantics, and the async Operation return shape plus the follow-up tool. Nothing an agent needs to call it correctly is missing.

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 the baseline is 3, but the description adds real constraint information not present in the schema: the accepted build formats (.apk/.aab for Android, .ipa for iOS). That helps the agent validate filePath before calling, beyond the schema's generic 'absolute local path' wording.

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 ('Uploads a build ... to Firebase App Distribution') and immediately scopes the accepted artifact types. It is clearly distinguishable from siblings like firebase_appdistribution_distribute_release and firebase_appdistribution_list_releases, which do different things to the same release resource.

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 explicitly names the next step ('Follow up with firebase_appdistribution_distribute_release to notify testers'), which routes the agent correctly in the workflow. It does not state preconditions (e.g. auth/permission requirements) or when not to use it, so it stops short of full when/when-not guidance.

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