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

Beyond annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false) the description discloses the upload validation gate — real Android app, 64-bit ARM, no root/system tools — and that failures are refused 'with the reason', which matters for retry logic. It also clarifies installs are repeatable rather than one-shot. The gap is that op=delete, though present in the schema, is never described, so the agent gets no behavioral context for the one removal path.

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?

It is front-loaded with the resource definition first, the upload/install lifecycle second, and the Play Store exclusion third, so an agent can stop reading once it has what it needs. The parenthetical validation list is dense but each clause carries information; only the closing run(files=...) sentence feels appended rather than integrated.

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 four ops, no required parameters, and an output schema present, the description covers enough for an agent to act: what the resource is, the two main operations, pre-staging, and the alternative path. The omission of op=delete and of any mention of listing behavior leaves a small but real hole for a narrative that otherwise reads as complete.

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 all four parameters are already documented, and the description largely restates the upload→install id flow rather than adding format or constraint detail. Its one useful addition is the cross-reference that the app id comes from op=list or op=upload and that target phones 'must be running'. Baseline 3 is appropriate given the schema does the heavy lifting.

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 names a specific resource and its scope ('The user's own apps on Clousd: APKs they uploaded, kept in their private storage') and enumerates the concrete operations via op=upload / op=install. It also explicitly states what the tool is not ('Clousd has no catalog of other people's apps'), which separates it cleanly from `library` and from store-based acquisition.

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 gives the full lifecycle rule: upload an APK once, then install it by id on any phone 'as often as needed', plus a routing instruction for the alternative path ('for apps from Google Play, open the Play Store on the phone'). It further tells the agent to pre-stage an app with run(files=...), which is an explicit cross-tool handoff.

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