Get an infrastructure delta

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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, so the bar is lower. The description still adds real substance: the result is a set of resources added, removed and changed, and the comparison baseline shifts depending on `version`/`against`. The PR-branch prerequisite is noted but the failure mode for a non-PR diagram is not.

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 compact sentences, front-loaded with the core purpose, then branching cleanly into the no-version and with-version cases. No filler or redundancy.

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?

With no output schema, the description carries the burden of conveying the return shape, and it does so at a useful level (added/removed/changed resources). For a three-parameter read tool this is nearly complete; only the non-PR-branch edge case is unaddressed.

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 only 33%, and the schema documents only `graphId`. The description compensates by defining `version` as a timestamp obtained from list_versions and clarifying that `against` only matters when `version` is set, with 'live' meaning the latest parse. The 'previous' enum value is left to inference as the implied default.

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?

Specific verb and resource: 'Show what changed in a diagram's infrastructure,' with the two operating modes spelled out. It is implicitly distinguishable from siblings like get_diagram or list_versions by being a comparison operation, though no sibling is named explicitly.

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?

Clear contextual routing: omit `version` for a PR-branch delta, supply `version` (sourced from list_versions) to compare against the preceding version, or set `against` to 'live' for the latest parse. It stops short of stating what happens when `version` is omitted on a non-PR-branch diagram or when to prefer get_diagram instead.

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