marm_graph_impact

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 usefully mentions the 'graph-unavailable error if the graph backend is disabled or failed to start' and describes the output conceptually. However, it does not explicitly state whether the operation is read-only, whether any mutation occurs, or any authentication requirements, leaving some ambiguity.

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 front-loaded with a bold purpose statement, followed by usage, a bulleted parameter list, and return value. Every sentence earns its place, and the structure is clean and scannable. There is no redundant filler.

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?

Since there is no output schema, the description explains returns: 'graph impact response, or a graph-unavailable error.' It also clarifies in the opening that the response includes affected symbols and propagation distance. This covers the essentials, though a more structured breakdown of the response object would make it more complete.

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?

The input schema has 0% description coverage, so the description must compensate. It does so thoroughly by listing all four parameters with meanings and examples: 'since: git ref or date to compare from, e.g. HEAD~5, v0.5.0', 'depth: impact propagation depth, 1-5', and defaults for base_branch and project. This adds significant semantic value 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 opening line 'Blast radius of code changes: git diff → affected symbols + risk' precisely states the tool's function with a specific verb and resource. It clearly distinguishes from sibling tools like marm_graph_trace (trace specific symbols) and marm_graph_architecture (architecture view) by focusing on impact propagation from a git diff.

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 usage context: 'Pass `since` (a git ref/date) or a `base_branch` to compare against' and explains defaults for base_branch and depth. However, it does not explicitly name alternative tools or state when not to use this tool, relying on the purpose to differentiate from siblings.

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