study_preferences

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

Annotations only say it is a non-read-only, non-destructive, closed-world call. The description adds meaningful behavior beyond that: locale=auto follows the user's language, BCP 47 tags are accepted, timezone is independent and defaults to Europe/London, and writes persist across hosts sharing the data directory. Persistence scope is a genuinely useful disclosure for a mutation tool.

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 read/update dual purpose before the semantic details. Every clause carries information; it avoids filler and stays compact for a four-parameter 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 mutate-or-read tool with no output schema, no annotation detail, and 0% schema coverage, the description covers the important behavioral facts but omits the meaning of two parameters and says nothing about what a read returns. Adequate 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 0%, so the description must carry parameter meaning. It documents locale (auto, BCP 47) and display_timezone (IANA, Europe/London default) in useful detail, but says nothing about bilingual_titles or include_languages, leaving half the parameters undocumented anywhere.

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 pair and resource ('Read or update local language/display preferences'), which is far more informative than the bare tool name. It does not explicitly distinguish itself from any sibling, but none of the listed siblings overlap with preference management, so 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?

Gives an explicit operational rule for the read path: 'No parameters reads only; each supplied field persists'. That tells the agent when the call is a read versus a write without needing to inspect defaults. It stops short of naming alternatives or exclusions, so it is clear context but not full when/when-not guidance.

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