Add answers to a recorded decision

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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=false, so the agent knows this mutates state harmlessly. The word 'merge' usefully signals additive/partial-update semantics rather than a full overwrite, but the description says nothing about permissions, error behavior on a missing episode_id, or how conflicts in merged fields are resolved.

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?

A single well-formed sentence with the action and the destination front-loaded and no filler. It is efficient, though it is arguably too terse to carry the behavioral context a mutating tool needs.

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 mutation tool with no output schema and a nested 'changes' object, the description covers the core intent but omits what the amended decision looks like afterward, whether the prior state is preserved, and the relationship to twin_record_decision. Adequate as a minimum but with clear 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 67% and the schema already documents 'changes' (merge semantics against record_decision names) and 'request_id' (idempotency key). The description adds the framing that changes are the principal's follow-up answers, but leaves episode_id entirely unexplained beyond its name.

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 ('merge') and resource (recorded decision) plus the source of the content (the principal's answers to follow-up questions). This distinguishes it from twin_record_decision (which creates the decision) and twin_record_correction, though it does not name those siblings 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?

The mention of 'follow-up questions' implies the usage context (amending an already-recorded decision with answers gathered from twin_next_questions), but there is no explicit when-to-use/when-not-to-use guidance or reference to the alternative tools twin_record_decision and twin_record_correction.

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