nanomem_history

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

With no annotations, the description carries the burden. It discloses output format (oldest first, current marked, last entry is current) and the edge case that a fact that never changed returns a single entry, not empty. It doesn't explicitly state read-only nature or handle missing facts, but these are implied or minor gaps. The behavioral context goes beyond a simple 'returns history'.

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 a single paragraph of moderate length, front-loaded with the core definition. Each sentence adds value: definition, usage, edge case, and sibling comparisons. It is not overly verbose, though it could be tightened.

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?

The description explains the return format and edge case (single entry for unchanged facts), and provides usage context. It lacks explicit mention of behavior for nonexistent facts, but the core functionality is adequately covered for a simple query tool. The absence of an output schema is compensated by the explicit description of the return structure.

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% with descriptions for both 'query' and 'max_len'. The description does not add any parameter-specific meaning beyond what the schema provides. The baseline of 3 applies since the schema does the heavy lifting.

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 the tool's function: 'Every value a fact has held, oldest first, with the current one marked.' This is a specific verb (trace/history) and resource (fact values). It also distinguishes from siblings by naming alternatives (nanomem_search, nanomem_changes) and explaining their different scopes.

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 states when to use: 'Use this when the user asks what something used to be, when it changed, or whether it changed at all.' It also provides exclusion guidance, noting when nanomem_search or nanomem_changes might be more appropriate, giving clear routing to alternatives.

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