Code Age Analysis

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

Annotations already mark this as read-only, lowering the bar. The description adds meaningful behavioral context beyond annotations: the requirement to provide repo_path when not in a git repo, and the interpretation of results (stale vs actively maintained files). It does not contradict the readOnlyHint.

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 description is concise—three sentences plus a note—and each sentence contributes distinct value: purpose, interpretation, use cases, and a critical requirement. It is front-loaded and contains no superfluous content.

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?

The tool is read-only with well-described parameters and a clear purpose. The description covers key use cases and the repo_path caveat, though it does not specify the exact output format. Given the lack of an output schema, this is a minor gap and does not hinder correct invocation.

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 baseline is 3. The description does not add meaning beyond the schema for sort, limit, or path_filter; it only reinforces the repo_path requirement that already appears in the schema. Thus it meets but does not exceed baseline.

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 clearly states the tool's function: 'Show the age of code in each file — when it was last modified.' It uses a specific verb and resource, and distinguishes itself from sibling tools by focusing on staleness versus active maintenance, which is not covered by other analysis tools.

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 provides clear use cases ('cleanup planning, onboarding, and understanding which parts of the codebase are actively evolving') and a critical prerequisite (repo_path if not in a git repo). However, it does not explicitly name alternative tools or state when not to use it, so it falls short of perfect exclusion guidance.

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