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

Annotations already declare destructiveHint=true, idempotentHint=false and readOnlyHint=false, so the mutation profile is covered. The description adds real context beyond that: a hard 20MB decoded-size cap, a metacharacter restriction, and the return shape. It does not state overwrite/conflict behavior, which keeps 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?

Four tight sentences, front-loaded with the action and destination policy before the size cap, safety rule, sibling redirect, and return shape. No filler or restatement of the name/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?

No output schema exists, but the description still gives the return shape ({ ok, remotePath, sizeBytes }). With all three parameters documented and the key limits and constraints stated, nothing an agent needs to call this safely 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 meaning the schema lacks: the enumerated allowed prefixes, the base64 encoding of content, the 20971520-byte decoded cap, and the metacharacter rule for remotePath. Only udid is left to the schema alone.

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 ('Push a base64-encoded file to the device') and goes further by naming the allowed destination roots. It also differentiates from the app_install sibling for the APK case, so an agent can route correctly without opening a 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?

Explicitly says where files may go ('/sdcard/' or '/data/local/tmp/') and gives a when-not rule plus the alternative: 'For APKs, prefer app_install instead.' The path precondition (no shell metacharacters) is also stated as a usage constraint.

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