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

Beyond the destructive/non-idempotent annotations, the description discloses the critical hidden contract: the URL is returned in `uploadUrl`/`headers`, must be PUT to with exactly those headers, and expires in one hour. That signing/expiry behavior is exactly the kind of context annotations cannot carry.

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-loads the step number and the checkout gate, then the return values and the curl example. Dense but purposeful; the inline example slightly lengthens it but earns its place by pinning the exact invocation.

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?

Even with no output schema, the description names the returned fields and the follow-up call, and states the expiry window. For a multi-step mutation tool this is complete enough to invoke correctly on the first try.

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 description coverage is 100%, and the schema itself explains name, contentSize (signed-length constraint) and applicationId in detail, so the baseline is 3. The description adds only the implicit tie between the zip and contentSize via the checklist/game.zip flow, not new parameter semantics.

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+resource ('start an archive upload') and frames it as 'Step 1 of 3 of uploading a build', which immediately distinguishes it from confirm_archive_upload and start_cover_upload. An agent knows exactly what this tool initiates.

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 prerequisite ('read get_game_checklist and check the build against each item first') and an explicit successor ('then call confirm_archive_upload'), plus the deadline ('within an hour'). The when-to-use path is fully prescribed rather than inferred.

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