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

Annotations only give a generic non-read, non-destructive, non-idempotent profile; the description adds real behavior: changes to a live version apply immediately, enabled=false disables URLs while preserving the list, and stale revisions must be re-read rather than blindly overwritten. It also explains the data-space='download:...' rendering contract, which no annotation covers.

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?

The core action and prerequisite are front-loaded, and most sentences carry distinct information (defaults, conflict handling, immediate effect). It runs long and the trailing data-space sentence is somewhat tangential, keeping it from a 5.

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 mutation tool with a nested config object and no output schema, the description covers inputs, defaults, and failure handling well. It omits what the call returns (e.g., a new revision) and any permission/auth expectations, which are the remaining gaps.

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?

With 0% schema description coverage the description carries the load and does so well: source-or-null, ordered attachments, required label vs optional description/downloadName, showFilename defaulting false, extension preservation, and enabled semantics are all explained. It leaves the `schema` const and `version_id` unmentioned, so not a full 5.

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 opens with a specific verb and resource plus scope: 'Replace an approved version's download settings without reuploading its content.' That distinguishes it from read/set siblings by making clear it mutates config rather than content or reads state, and it explicitly routes reads to get_downloads.

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 names the prerequisite read step ('Read get_downloads first for its revision and candidates') and prescribes conflict behavior ('read and review again; do not overwrite blindly'). It stops short of explicitly contrasting with preview_downloads or stating when not to call it, so it falls just short of a full 5.

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