Brain History

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

The readOnlyHint annotation already indicates no side effects, and the description reinforces this by referring to a 'record' and 'what happened before'. It adds context about the content (failures, successes, false positives, true findings) but does not detail output format or limitations. Since annotations cover the key behavioral trait, the description adds some but not extensive value.

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, front-loading the purpose. There is slight redundancy between 'what happened before, in order' and the enumeration of outcomes, but it remains concise and readable.

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?

An output schema is present (from context), and the description gives a clear sense of what data is returned (historical tool calls across engagements) and how it can be filtered. The omission of 'event' and 'limit' semantics is a minor gap, but the overall context is sufficient for an agent to decide when to invoke this 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?

The description explicitly mentions three of five parameters as filters ('phase, tool, or outcome'), but leaves 'event' and 'limit' unexplained. With zero schema description coverage, this partial explanation is helpful but incomplete.

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 states this tool retrieves a historical record of tool calls ('every sensed tool call across engagements') with filtering options ('filterable by phase, tool, or outcome'). The metaphorical language ('brain's episodic memory') does not obscure the core purpose.

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 does not provide explicit guidance on when to use this tool versus sibling tools like brain_recall or memory_recall. It only describes what it does, without stating conditions such as 'use this when you need to review past tool executions' or contrasting with alternatives.

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