play_signing_sha1

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

With no annotations, the description carries the full burden and does well: it discloses the Google re-signing behavior, the source artifact (deployment_cert.der), and that the visible UI value is the wrong key. It does not cover auth requirements or what happens if package_name is invalid, keeping it short of a 5.

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?

Front-loaded with the core action, then the diagnostic scenario, then the caveat. Every sentence adds real value, though the symptom narrative is a bit long relative to the two-parameter operation.

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?

An output schema exists, so return values needn't be spelled out, yet the description still explains the SHA-1 payload. The main gap is the unknown parameter semantics and the file side-effect of writing to download_dir, which matters for an unannotated tool.

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 0%, so the description must compensate. It implies purpose for both parameters (package_name identifies the app, download_dir receives the downloaded certs) but never specifies format, path semantics, or whether download_dir must exist. Adequate but incomplete.

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 (download), resource (Play's app signing certificates), and output (SHA-1 of each). It is clearly distinguishable from unrelated siblings like store_audit_identity or apple_register_bundle_id, and even clarifies which certificate is involved (deployment_cert.der).

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 an explicit trigger scenario ('Sign in with Google' works locally but fails with the store APK, account picker loops with no error) and explicitly warns against using the wrong value (the upload key's SHA-1 on the App signing page). It also names where the output is consumed (Android OAuth client in Google Cloud Console).

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