Send a single control key such as Enter, Tab, Esc, Ctrl-C, or arrow keys to a terminal session, enabling input submission, interruption, and prompt navigation.
Send one control key: enter, tab, esc, backspace, ctrl-c, ctrl-d, ctrl-u, ctrl-l, ctrl-z, ctrl-r, up, down, left, right, q, y, n. Note 'enter' submits whatever is typed.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | ||
| session | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and openWorldHint=true, so the safety profile is covered. The description adds a genuinely useful behavioral fact ('enter' submits whatever is typed), but says nothing about session targeting, focus, or what a destructive key press does to running processes.
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?
Compact and front-loaded: the verb and resource lead, the key list follows, and the one behavioral caveat is last. The long enumeration is justified by the absence of a schema enum, though it makes the sentence slightly list-heavy.
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?
An output schema exists, so return values need not be explained. However, for a destructive, open-world tool with an undocumented session parameter, the description is incomplete: it never explains session scoping or what 'enter' submitting text means for the terminal state.
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 0%, so the description must carry the parameter burden. It does compensate for the missing enum by listing valid key values, but it completely ignores the 'session' parameter and doesn't explain whether 'key' is case-sensitive or how the session is resolved.
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 ('Send one control key') and enumerates the exact key set, which is more precise than the vague schema. It implicitly distinguishes itself from send_text by the word 'one' and 'control key', but never names that sibling 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?
There is no explicit guidance on when to use this instead of send_text or run_command, which are both plausible alternatives for terminal interaction. The note about 'enter' is behavioral, not routing guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.