Close a currently valid fact assertion in persistent agent memory while retaining its history, optionally recording when it stopped being true and why.
Close a currently-valid fact assertion. History is retained.
| Name | Required | Description | Default |
|---|---|---|---|
| at | No | ISO 8601 time the fact stopped being true; default now | |
| object | Yes | ||
| reason | No | manually_invalidated | |
| project | No | general | |
| subject | Yes | ||
| predicate | Yes |
Changes observed during successful MCP inspections.
v14.7.0Input schema / properties / atAdded value: +{
+ "description": "ISO 8601 time the fact stopped being true; default now",
+ "type": "string"
+}v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare destructiveHint=true with no read-only/idempotency guarantees, and the description usefully clarifies the nature of that destruction with 'History is retained' – a genuinely additive behavioral fact. It still omits whether closing an already-closed fact is a no-op and any permission requirements.
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, front-loaded sentences that each carry information with no waste. Efficient, though extremely terse.
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 6-parameter mutation tool with 17% schema coverage and no output schema, the description is too thin. It never explains reason/project semantics or the temporal 'at' behavior, leaving an agent under-informed for correct invocation.
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 only 17% (just 'at'). The description supplies no meaning for subject, predicate, object, reason, or project, and does not compensate for the undocumented parameters. Only the bare concept of a 'fact assertion' is implied.
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+resource: 'Close a currently-valid fact assertion.' An agent can tell this is a write operation on an existing fact. However, it doesn't explicitly contrast with the obvious sibling kg_add_fact, so it isn't a 5.
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 'currently-valid' qualifier hints that only valid facts should be closed, but there is no explicit when-to-use, when-not-to-use, or mention of alternatives like kg_add_fact. Guidance is left entirely to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.