Set a local background (verified)

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

With no annotations provided, the description carries the burden of disclosing behavior. It mentions validation, symlink confirmation, and the 'never downloads or copies' side effect, which adds some transparency. However, it does not describe error behavior on invalid input, permission requirements, or whether the previous background is overwritten, leaving notable gaps 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?

The description is two sentences with zero filler. It front-loads the purpose, then adds the key constraint ('Never downloads or copies files') without redundancy. Every phrase earns its place.

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 one-parameter tool with no output schema or annotations, the description covers the essential aspects: what it does, the type of input, and a key behavioral constraint (no downloads). It stops short of explaining failure modes or return format, but the 'confirm symlink' hint partially addresses output. Overall it is nearly complete for an agent to call 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?

Despite 0% schema description coverage, the description adds critical meaning to the sole 'path' parameter by specifying it must be an 'absolute local image'. This goes beyond the schema's generic pattern/length constraints and clarifies what kind of path is valid, effectively compensating for the lack of schema description.

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 states a specific verb ('Set'), a clear resource ('local background'), and adds distinguishing constraints: 'strictly validated absolute local image' and 'confirm the Omarchy state symlink'. This clearly differentiates it from sibling tools like theme_bg_next (cycling) or background_current_details (querying) and leaves no ambiguity about what the tool does.

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 provides implicit usage context: it is for local images only and explicitly says 'Never downloads or copies files', which signals that remote or non-local sources are out of scope. It does not explicitly name alternatives or state when not to use it, but the local-only constraint is enough to guide an agent away from this tool for network operations.

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