plc_rename_variable

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

Goes well beyond the annotations by disclosing atomic staging, the rejection conditions (incomplete affected source, collisions, reference capture), the returned new variable ID, and the explicit exclusion of IDE builds and external-consumer updates. This is exactly the mutation-behavior context the annotations alone do not convey.

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 dense sentences, front-loaded with the action and scope, then the prerequisite, then the failure modes and exclusions. Telegraphic phrasing ('reject incomplete affected source') is efficient but slightly compressed.

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?

An output schema exists so return values need not be explained, and the description covers atomicity, rejection behavior, and scope limits for a mutation tool. The remaining gap is the undocumented parameters, which leaves the definition short of fully self-sufficient.

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 25% (only expected_revision is documented), so the description must compensate, but it says nothing about transaction_id, variable_id, or new_name semantics. The only parameter-adjacent hint is the returned new variable ID.

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 ('Recompute and stage a guarded variable rename') plus the exact scope ('across declarations, ST and LD'), which separates it from plc_plan_rename and plc_update_variable without opening either schema.

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?

Explicitly requires 'Read plc_plan_rename first', giving a clear ordering constraint against the sibling planner, and bounds scope with 'No IDE build or external-consumer updates are implied'. It does not explicitly contrast with plc_update_variable, so it stops short of full when/when-not coverage.

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