Build background thumbnail cache (verified)

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

With no annotations provided, the description carries the full burden. It discloses that the tool verifies signature, rows, and output files, which adds behavioral context. However, it does not mention whether the build is destructive, whether it overwrites existing files, or any permissions required. The verification detail is useful but not comprehensive, so a 3 reflects the partial disclosure.

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 a single, well-structured sentence that leads with the core action and includes the verification step. It is concise, front-loaded, and every phrase adds value. No filler or repetition exists.

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 tool with no parameters and no output schema, the description covers the essential purpose and the verification behavior. It is complete enough to guide an agent on invocation, though it does not elaborate on potential side effects or typical usage scenarios. Still, given the simplicity, it is well within the acceptable range.

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?

The tool has zero parameters and no output schema. The description does not need to explain parameter semantics since there are none. The baseline for zero parameters is 4, and the description adds no unnecessary parameter information, fulfilling the requirement without redundancy.

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 explicitly states the action (build), the resource (current-theme thumbnails), and the method (through Omarchy), plus a verification step. This makes it clear what the tool does and differentiates it from siblings like background_thumbnail_cache_status, which is about status rather than building.

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 clearly conveys the context: building thumbnails for the current theme. While it does not explicitly mention alternatives or exclusions, the intent is unambiguous, and the sibling status tool is naturally understood as the complementary check. A score of 4 is appropriate because it provides clear context without explicit when-not guidance.

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