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

No annotations are provided, so the description carries the behavioral burden. It discloses upsert/replce semantics, the allowed fact types, and the conditional If-Match behavior via rev. It does not mention auth requirements, side effects on derived CALC values, or what happens when no rev is supplied, but it gives much more than a minimal mutation description.

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?

Three compact sentences front-load the core operation, then add a concrete example and the critical restrictions. Every sentence earns its place, and no schema information is redundantly repeated.

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 an 11-parameter mutation tool with no annotations and no output schema, this description provides the essential upsert model and constraints but is not fully complete. It does not describe the value property, the nested source contract, identity fields like scopeKey/id, or failure behavior without a rev, leaving advanced calls partially underspecified.

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 27%, so the description must compensate. It clarifies the composite identity (parameterId + scope + setId) and the meaning of valueOverride and rev, but it leaves value, source, evidenceStatus, valueLocked, and scopeKey unexplained; the value parameter is notably absent from the prose despite being central to writing a fact.

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 action 'Create or replace one fact' and defines the unique key as parameterId + scope + setId. The wording 'one fact' distinguishes it from the plural sibling model_upsert_observations, and the concrete example 'Base P2 facility MW' anchors the tool to a real use case.

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?

Provides explicit usage constraints: only IN facts or CALC overrides (valueOverride) should be written, not CALC-computed values, and rev should be passed for If-Match. It does not explicitly name the plural sibling for batch usage, so it stops short of complete alternative routing.

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