press_key

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

With no annotations, the description carries the full behavioral burden and does so: multi-agent tab ownership rules, rejection code TAB_NOT_OWNED, a configurable session cap (default 8, range 1-64), tab_id auto-resolution, and the change_report payload inclurating truncation hints. This is unusually rich disclosure for a zero-annotation 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?

Purpose is front-loaded in the first sentence, followed by terse labeled sections (When to use, Related, Multi-agent, RETURNS). It is longer than average, but every block carries distinct operational information and no sentence is pure 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 a tool with no output schema and no annotations, the description supplies the missing pieces: return shape (change_report fields), truncation behavior with a follow-up pointer to read_page, cross-agent error semantics, and tab ownership rules. An agent has what it needs to call it correctly and interpret the response.

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 coverage is 100% so the schema already documents modifiers and key format, giving a baseline of 3. The description edges above baseline by adding usage context for tab_id (pass only when the agent owns multiple tabs; auto-resolves otherwise) and the session cap, which the schema wording does not convey.

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 and resource (press a keyboard key) plus scope (optional ctrl/shift/alt modifiers) and explicitly routes to siblings press_enter, type_text, and focus. An agent can distinguish this from all nearby keyboard/input tools without opening schemas.

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?

Includes an explicit 'When to use' section covering shortcuts, special keys, and key combinations, and names the related alternatives with their differing intent (press_enter for Enter, type_text for full strings, focus to pre-focus). Both the use case and the routing are stated, not inferred.

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