Swipe

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

Annotations already declare the write/idempotency profile (readOnlyHint=false, idempotentHint=false), so the description's job is to add context, which it does: it explains that verify="ui" returning "unchanged" typically signals the end of a scrollable list rather than a no-op. That result-interpretation guidance is genuinely useful and not derivable from annotations or schema. It stops short of covering failure modes or return shape.

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 core geometry and timing before the long-press and TV caveats. Slightly reliant on cross-references to adb_tap for coords/verify semantics, which costs a little, but there is no filler.

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 an 8-parameter input-injection tool with no output schema and annotations that only cover the safety profile, the description covers the non-obvious cases an agent would otherwise get wrong: the long-press threshold, shared coordinate space, and the interpretation of a verify="ui" unchanged result. Only the failure/return behavior remains unaddressed.

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 100%, so the baseline is 3, but the description adds real semantic content beyond the schema: the default 300 ms duration, the >= 800 ms long-press threshold rule, and the fact that both endpoints share a single coordinate space. Those are behavioral constraints the schema does not encode.

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?

Opens with a specific verb plus explicit geometry and timing ('Swipe from (x1,y1) to (x2,y2) over duration_ms'), which is unambiguous and clearly distinct from adb_tap, adb_key, and adb_find_and_tap. It also defines the long-press variant, so the agent understands the tool covers more than literal swipes.

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 concrete when-to-use routing: use adb_key DPAD_* on a TV box without a touchscreen, and use the same-point + duration_ms >= 800 form for a long-press. It also names the sibling whose conventions it inherits (adb_tap for coords and verify), so the agent knows where to look for the shared semantics.

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