session_press

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

With no annotations, the description carries the full burden and does well: it discloses the return value ({ok: true}), the 409/404 error semantics, and the session prerequisite. It does not state whether the press waits for any resulting navigation, which leaves a small gap for an input 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?

Front-loaded with the core action, then structured Args and Returns sections with zero filler. Marginally longer than strictly needed, but every line carries information.

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?

No output schema exists, and the description supplies the return shape and error codes. Combined with the prerequisite and key-format guidance, 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 coverage is 0%, so the description must compensate and does: 'name' is defined as the identity name exactly as profiles_list reports it, and 'key' is defined as a key or chord with concrete Playwright examples ('Enter', 'Tab', 'Control+A'). This adds real semantics well beyond the bare string schema.

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 on the session's current page', with the target clarified as 'whatever is focused'. It is distinguishable from siblings like session_click_selector and session_fill_selector, though it never names them explicitly.

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?

Clearly states the prerequisite ('Requires a session opened with profile_start first') and the failure path if that precondition is unmet (409 — call profile_start first). It gives clear context for use but does not contrast against alternative input tools such as session_fill_selector.

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