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

The description discloses behavioral traits beyond annotations: persistence across sessions, default filtering to accepted brushes, the ability to include rejections with reason, and scoping to space or all spaces. It aligns with the readOnlyHint annotation, indicating a safe read operation.

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 relatively concise with four sentences, front-loading key information. Each sentence adds value, though it could be slightly more streamlined without losing detail.

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 the tool's simplicity (no output schema, 4 params, no enums), the description is complete. It includes a useful summary of each returned field (e.g., tsMs, spaceSlug, center), which helps the agent understand the output format despite lacking an output schema.

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 adds meaning to all four parameters: explains default limit (50), space scope (recommended current space, omit for all spaces), since_ts_ms time filter, and accepted_only toggle with default true. It compensates for the 50% schema description coverage by providing context for undocumented parameters.

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 it retrieves the user's own brush history, specifying it is persisted across sessions and defaults to accepted brushes. It distinguishes from siblings like 'get_build_info' and 'recent_memory' by focusing on brush operations and providing specific use cases.

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 provides explicit use cases: use at enter_space to recall previous builds and before building to avoid duplication. It also explains parameter options like accepted_only for viewing rejections. However, it does not explicitly state when not to use the tool or compare directly to siblings.

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