compare_branches

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

Description states read-only, resolves merge-base automatically, groups results, includes blast radius and risk assessment, and returns JSON format. Annotations already indicate readOnlyHint, destructiveHint, idempotentHint; description adds valuable behavioral context.

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?

Two sentences, front-loaded with purpose, then usage and output. No unnecessary words.

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?

Given no output schema, the description details output structure (JSON with branch, base, mergeBase, changes, summary). Covers grouping and risk assessment adequately for a complex tool.

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% but description adds meaning: explains grouping (category/file/risk) and blast radius depth, which aligns with parameters group_by and max_blast_depth. Adds context beyond 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?

Description clearly states it compares two branches at symbol level, listing additions, modifications, removals. It distinguishes from sibling get_changed_symbols by specifying comprehensive vs quick.

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?

Explicitly says 'Use for comprehensive PR comparison' and contrasts with get_changed_symbols for quick list. Also mentions 'Requires git'.

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