set_key

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

With no annotations, the description carries the full burden. It discloses file placement logic and warns on placeholder mismatch, which is useful. However, it doesn't mention overwriting behavior, error handling, or permission requirements, leaving some important behavioral traits undisclosed.

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 three short sentences, each contributing distinct value: purpose, file selection logic, and placeholder warning. There is no fluff or repetition.

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 moderate-complexity tool with no output schema and no annotations, the description covers the core behavior and important edge cases (file selection, placeholder warning). It doesn't explain return values or error states, but for a mutation tool this is acceptable. The description is sufficiently complete for an agent to use it correctly.

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 100%, so the baseline is 3. The description adds extra meaning by explaining how the optional 'file' parameter falls back to the current file, nearest prefix, or locale default. It also hints at validation of 'values' via placeholder mismatch warnings.

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 uses a specific verb+resource pair ('Create or update a key per locale') and clearly distinguishes this from sibling tools like get_key, delete_key, and search. It also explains the file selection behavior, which further clarifies the tool's scope.

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 conveys clear context for when to use this tool: when creating or updating a key per locale. It doesn't explicitly name alternatives or exclusions, but the purpose is unambiguous enough for an agent to select it over read/search/delete tools.

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