recall_stats

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

Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds significant behavioral context by defining the staleness threshold (older than 2 days) and the exact return shape, which goes beyond annotations.

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 concise: three sentences with front-loaded purpose, a clear definition of 'stale', and a compact return schema. No redundant phrases or unnecessary details.

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?

For a zero-parameter stats tool, the description is fully complete. It explains what it does, the freshness definition, and the return structure. No additional context is needed given the output is also documented in the description.

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?

There are zero parameters, so the schema covers everything. The description adds value by explaining the output fields (chunks, newest_indexed_at, stale) and their meaning, which is not present in the input 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 states the tool reports memory size and staleness, using specific verb 'report' and defined resource ('memory'). It also distinguishes itself from sibling tools by focusing on statistics/freshness rather than search, indexing, or forgetting.

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 frames usage explicitly: 'Report how much memory exists and whether it is stale (freshness check).' This gives clear context for when to use the tool, though it does not mention when not to use it or name alternatives.

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