planist_update_variable

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

With no annotations provided, the description carries full responsibility for disclosing behavioral traits. It explicitly mentions that updating triggers reactive UI updates across Sheet cells, Dashboard widgets, and Docs, which is a non-obvious side effect. It also references the 'Plan loop' context. Missing are permission requirements, reversibility, or failure modes, but the disclosed reactive behavior adds significant value beyond the schema.

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 two sentences, front-loaded with the primary action in the first sentence. The second sentence adds valuable behavioral context without redundancy. Every word earns its place; it is appropriately sized for a simple update tool.

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 3-parameter, 100% schema-covered update tool with no output schema, the description is largely complete. It explains what the tool does, the trigger effect on the reactive UI, and the loop context. It does not mention prerequisites like permissions or error handling, but these are not critical for a straightforward variable update, and the schema covers parameter semantics. A score of 4 reflects that it goes beyond the minimum viable description.

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 100%, so the baseline is 3. The description does not add parameter-level details beyond what the schema already provides. It repeats 'typed' and 'strict type contract' from the schema but does not clarify value formats, constraints, or optionality beyond the schema descriptions. No compensation needed, but also no added value.

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 the tool's action: 'Update a typed project variable value.' This is a specific verb+resource combination. The sibling tools are all read-only or propose operations (list, read, get, propose), so 'update' uniquely distinguishes this as the mutation tool for variables.

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 implies usage (when you need to change a variable value) but does not explicitly contrast with alternatives or state exclusions. It provides useful context about reactive UI updates and the 'Execute -> Variable -> Plan loop,' which helps the agent understand the impact, but it does not say 'use this instead of get_variable for modifying values.'

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