Retrieve relevant past lessons using BM25 ranking before starting tasks or when facing unexpected issues.
Search past lessons by relevance (BM25). Use before starting work, and whenever something surprises you.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max results (default 5). | |
| query | Yes | What you are about to do, in words. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden of behavioral disclosure. It reveals the BM25 relevance algorithm, which is useful, but it does not explicitly state that the tool is read-only or has no side effects. For a search tool this is likely implied, but the absence of any annotation or side-effect disclosure leaves some ambiguity.
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 only two sentences, with the first sentence stating the core purpose and the second giving usage guidance. Both sentences earn their place, and critical information is front-loaded.
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 simple two-parameter search tool, the description is adequate: it explains what it does and when to use it. However, since there is no output schema and no annotations, the description could mention what the returned data looks like or that it is informational-only, but given the tool's simplicity, this is a minor gap.
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 description coverage is 100%, with both parameters already documented in the input schema. The description itself adds no new parameter-level detail beyond what the schema provides, so the baseline of 3 applies.
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 searches past lessons by relevance using BM25, which is a specific verb (search), resource (past lessons), and method (BM25). This distinguishes it from sibling tools like ddflow_history or ddflow_recall, which likely have 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?
The description explicitly instructs to use the tool 'before starting work' and 'whenever something surprises you,' providing clear timing and context for invocation. It does not mention when not to use it or name alternatives, but the guidance is actionable and sufficient for this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.