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

The annotations already establish this is a non-read-only, non-destructive, non-open-world operation, so the bar is lower. The description adds that the snapshot is named and later restorable/comparable, which is useful context, but it omits key behavior: whether a duplicate label overwrites an existing version, whether unpinned changes are required, and what happens on failure. A 3 reflects modest added value beyond the annotations.

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?

Two short sentences with the core action and example up front, and the workflow advice second. No filler, no restating the 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?

For a two-parameter, low-complexity tool with no output schema and clear annotations, the description supplies what an agent needs to act. The remaining gap is version-identity semantics — how labels interact with list_versions/compare_versions and whether re-saving a label collides — which is minor but worth noting.

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 50%: projectId is documented in the schema while label is bare. The description partially compensates by showing an example label format, but it doesn't state whether labels must be unique, whether they're user-visible in the version list, or a length/charset constraint. Baseline-3 territory given the schema covers the default-project parameter.

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 — saving a named snapshot of the timeline — and the quoted example ("v2: tighter hook") concretizes what a label looks like. The mention of 'compare against or restore' signals the sibling concepts (compare_versions, restore_version, list_versions) without ambiguity.

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 recommends calling it 'before each round of revisions', which gives an agent a clear trigger condition. It doesn't name alternatives or state when not to use it, but the intended workflow is unambiguous.

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