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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description rightly focuses on adding context beyond them: returns `{revisions: []}` with no paging, the four fields per entry, and error conditions for missing or unmatched lineKey. This meaningfully enriches the contract without repeating annotation data. It doesn't contradict 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?

Three sentences, zero filler: purpose with ordering, return shape with fields and paging behavior, and error conditions. The most decision-relevant fact (what it lists and why) is front-loaded, and every sentence earns its place.

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 single-parameter read-only tool with no output schema, the description covers everything needed to call it correctly: purpose, ordering, return shape, fields, paging, and error conditions. The description compensates fully for the missing output schema, and nothing an agent needs is left ambiguous.

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% for the single required lineKey parameter, so the baseline of 3 applies. The description adds marginal value by explaining in the error clause that lineKey must match a line in the project, reinforcing validity semantics, but it doesn't add syntax or format details beyond the schema.

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 uses a specific verb-resource pair ('List every retained revision of one line') with ordering ('newest first') and ties the purpose to a concrete downstream action ('so a target revision can be picked for rollback_config'). This clearly distinguishes it from siblings like get_config, config_diff, and rollback_config without needing to open schemas.

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?

The description gives clear context by positioning the tool as the precursor to rollback_config, telling an agent when this tool is the right call. It stops short of a 5 because it does not explicitly name alternatives or state when NOT to use it (e.g., get_config for the current config), but the implied workflow is unambiguous.

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