brain_diff

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

No annotations exist, so the description must fully disclose behavior. It describes the tool as read-only (analogous to git log) and explains the output structure. However, it does not mention potential side effects, required permissions, or rate limits. The description is adequate but could be more explicit about its non-destructive nature.

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 two sentences plus an example, with the core analogy front-loaded. Every sentence provides unique value: analogy, behavior, use case, example output. No fluff.

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 3 simple parameters (all described in schema), no output schema, and no annotations, the description covers all necessary aspects: purpose, usage, example, and output format. It is fully standalone and actionable.

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?

Input schema coverage is 100%, so parameters are already documented. The description adds value by clarifying the purpose of each parameter in context: instance_id is the brain to inspect, since format options ('1d','7d','30d', ISO-8601) and default, format as summary/detailed. It also explains output structure, which compensates for lack of output 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 description clearly defines brain_diff as a diff tool for an AI brain, listing specific change categories (new, updated, recalled, decayed). It distinguishes itself from sibling tools like brain_from_git or brain_predict by focusing on temporal state comparison.

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 states it's 'perfect for weekly reviews' and provides an explicit example (brain_diff(instance_id=..., since='7d') → '12 new · 4 updated · 2 stale'). However, it does not explicitly exclude when not to use it or mention alternative tools for similar tasks.

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