drag_variable_speed

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

With no annotations, the description carries the full burden and largely meets it: it discloses the emitted event sequence (mousePressed / N mouseMoved / mouseReleased), the slow-fast-slow delay behavior, the multi-agent ownership constraint with the TAB_NOT_OWNED rejection, and the configurable cap (default 8, 1-64). It omits any statement of safety/reversibility for what is an input-simulating action, which keeps it short of a 5.

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?

Front-loaded correctly: purpose, event sequence, use case, and the sibling alternative all come before the ancillary notes. It is on the long side — the multi-agent and change_report paragraphs are verbose — but each section is scoped and none is 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?

There is no output schema, so the description must describe returns, and it does: the change_report fields (URL, dialogs_opened, nodes_added, nodes_removed, attrs_changed, inputs_changed, focus_shift), the truncation flag/hint, and the escalation to read_page. Combined with purpose, exclusion criteria, error case, and tab scoping, an agent has everything needed 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?

Schema description coverage is 100%, so the baseline is 3. The description supplies conceptual context for the timing parameters (the slow-fast-slow curve explains what steps/minDelayMs/maxDelayMs are doing) and repeats tab_id ownership semantics, but adds no syntax, ranges, or defaults beyond what the schema already documents.

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+resource with precise scope: 'Drag from one viewport coordinate to another at variable speed using an ease-in-out timing curve.' It names and differentiates its siblings — 'drag (uniform-speed drag for canvas/maps)' and 'drag_drop (DOM element-to-element drag)' — so an agent can disambiguate without opening a schema.

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?

Explicit when-to-use with an alternative: 'Essential for slider CAPTCHAs and puzzle CAPTCHAs where constant-speed drag is detected as bot behavior. For uniform-speed drag (canvas drawing, map panning), use the regular drag tool instead.' It also lists related tools and their distinct scopes.

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