add_fact

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

Annotations only provide readOnlyHint=false, so the description must disclose all behavioral traits. It extensively covers constraint checking with rejection, alias detection, temporal semantics (valid_to as open interval, supersession), and response formats (status, question_id). No contradictions with 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 quite long and dense, mixing examples and explanations in a stream-of-consciousness style. While information-rich, it lacks clear sectioning and could be more concise by separating parameter details from usage examples.

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?

Given the complexity (9 parameters, no output schema), the description covers most aspects: temporal model, constraint checking, alias detection. However, it does not explicitly state the success return format (e.g., fact ID) and omits explanation for the required 'branch' parameter, leaving minor gaps.

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 0%, so the description carries full burden. It explains all major parameters: chapter, valid_to, narrated_in, attribute, value, kind (with examples), subject, and num (via LEDGER). It adds critical meaning about temporal intervals and narrative timing that the schema lacks.

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 'register one fact' (事実を1件登録) with specific verb and resource. It distinguishes from sibling add_facts by using '1件', implying singular operation. Examples of attributes and temporal parameters solidify the purpose.

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 provides usage context: basic operation when writing from scratch, and examples of when to use valid_to (e.g., death). It mentions link_entities as an alternative for proactive alias handling, but does not explicitly compare to add_facts or add_setup for batch versus singular usage.

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