Trace an impression back to the source statements or earlier impressions it was formed from, so you can verify why you remember it and whether a dream fabricated it.
追溯一条印象是怎么来的：它由哪几句原话压出来、或者由哪几条旧印象再压出来的。用于自查『我为什么记得这件事』，也用于确认梦有没有编造。
| Name | Required | Description | Default |
|---|---|---|---|
| id | No | 也可以直接给印象 id | |
| text | No | 印象的大致内容，会找最接近的一条 |
Changes observed during successful MCP inspections.
v0.4.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden. It does disclose the shape of the result (a lineage chain of source quotes or prior impressions) and implies a read-only lookup, but says nothing about behavior when no match is found, whether results are truncated, or any permission/cost constraints.
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?
Two short sentences, front-loaded with what is traced and followed by when to use it. No filler or restatement of the tool name.
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?
With no output schema, the description usefully explains what the trace returns (source sentences or upstream impressions), which is the key unknown for an agent. Only failure/empty-result handling is left unstated.
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% and both properties are documented in the schema, including that `text` fuzzy-matches the nearest impression. The description adds no parameter-level detail beyond the schema, so the baseline 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?
States a specific verb and resource: trace the provenance of an impression — which source sentences compressed into it, or which older impressions it was recompressed from. That is clearly distinct from recall/observe/dream siblings, though it never names an alternative tool explicitly.
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?
Gives two concrete situations: self-checking 'why do I remember this' and verifying whether a dream fabricated content. That is real usage context, but there is no explicit when-not guidance nor a named sibling to use instead.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.