Types ASCII text into whatever has keyboard focus, one character at a time; use press_keys for Return and shortcuts.
Type text into whatever has the keyboard focus, a key at a time. ASCII only: a character with no key fails the call, once what's before it is typed. For keys and shortcuts (Return, ctrl+s), use press_keys.
| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | The text to type | |
| session | Yes | Its name, from start_session |
Changes observed during successful MCP inspections.
v0.7.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations mark this as a non-readonly but non-destructive write, so the safety profile is covered; the description adds genuinely useful behavior beyond that: typing is per-keystroke into the focused element, and a non-keyable character fails the call at the point reached. It does not disclose what happens to already-typed text on failure or any confirmation/return behavior, keeping 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?
Three tight clauses: purpose first, then the constraint/failure mode, then the sibling routing. Zero filler and well front-loaded.
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 two-parameter, no-output-schema tool this covers purpose, precondition, failure mode, and the alternative path. The only omission is any statement about success confirmation or partial-typing state, which is minor here.
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% (text and session are both documented, with session pointing back to start_session), so the schema already carries the parameter meaning. The description adds no per-parameter syntax or format detail, which is the expected baseline when the schema does the work.
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 concrete verb ('type') and resource ('text into whatever has the keyboard focus') plus the granularity ('a key at a time'). It explicitly differentiates itself from the sibling press_keys, so an agent can disambiguate without opening either 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?
It names the alternative tool and the exact condition that selects it ('For keys and shortcuts (Return, ctrl+s), use press_keys'), and states the ASCII-only precondition that governs whether the call should be made at all.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.