Set Where You Live and Apply

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

Beyond the annotations, the description discloses atomic all-or-nothing save behavior on a refused field, retention of stored answers for dropped markets, the meaning of [] for apply_in, and the no-argument read behavior. It also describes the return object and how setup can be null. This is rich behavioral context for a mutation tool and does not contradict the 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 front-loaded with the core purpose and is dense with useful clauses rather than filler. It is somewhat semicolon-heavy and run-on, which slightly reduces readability, but almost every clause earns its place given the complex partial-update semantics.

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 three-parameter mutation tool with no output schema, the description supplies the return shape, atomic failure behavior, partial-update semantics, and edge cases for each parameter. Nothing an agent needs in order to call it correctly appears to be missing.

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 coverage is 0%, so the description must carry parameter meaning, and it does: home is a market key like 'UK' not 'GB' and controls date format and fallback currency; apply_in lists every applied market and [] means home alone; home_currency is ISO 4217 and an empty string follows home again. These details add real semantics beyond the enum-only schema.

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 opens with a clear verb and resource: 'Save where the user lives and applies,' and explains that home controls date format and currency while apply_in controls application markets. It does not explicitly name or contrast sibling tools such as set_persona or set_job_preferences, so sibling differentiation is implicit rather than stated.

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 explains how the fields interact, including that passing no fields reads current values and that only passed fields change. However, it never states when to use this tool instead of related scheduler-profile or preference tools, so usage guidance is implied rather than explicit.

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