ctx_changed

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

With no annotations, the description carries the full burden of behavioral disclosure. It reveals the JSON return, the default inclusion of working-tree changes, the behavior when ref is omitted, and the error case for non-git repositories. This is substantial and gives an agent accurate expectations beyond the tool name.

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?

Four short sentences with the core behavior first, then usage context, parameter explanation, and the sibling alternative. Every sentence contributes distinct information and there is no filler or repetition.

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 definition is complete enough for a single-optional-parameter tool: it covers output type, parameter semantics, non-git failure, and the sibling distinction. However, with no output schema it does not detail the JSON shape or define what a 'symbol' is, which leaves slight ambiguity about the exact return structure.

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 the baseline is 3. The description adds value by providing concrete ref examples (HEAD~5, main, a SHA) and by clarifying the default working-tree behavior, but it mostly reinforces what the schema already states for the single optional 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?

The description opens with a specific verb and resource: 'Return files and symbols changed since a git reference as JSON'. This clearly states what the tool produces, distinguishes it from siblings like ctx_diff, and includes the working-tree default. It is not a tautology and conveys the tool's exact scope.

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 explicitly explains when to use the tool ('focus an agent on what changed ... before reviewing or testing') and names the alternative for a different need ('For a per-symbol semantic diff between two refs use ctx_diff'). It also states the git-repository precondition, so an agent knows when the call will fail.

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