SassyMCP

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sassy_session_start

Destructive

Start a persistent named terminal session for long-running work like dev servers or builds, then poll its output and stop it when done.

Instructions

Mutating: spawns a persistent terminal session under a unique name and returns its status, shell, and pid. shell defaults to the host native shell (powershell/cmd/wsl on Windows; bash/zsh/sh on macOS/Linux); command optionally runs immediately after startup. Reuse of a live name and initial commands tripping the delete interceptor are refused. stderr is merged into stdout and the per-session buffer keeps the last 50000 characters (tail). Use it for long-running work like dev servers or builds that you poll with sassy_session_read; use sassy_shell for one-shot commands and stop sessions with sassy_session_stop when done.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`name`	Yes
`shell`	No
`command`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv1.15.1Sep 18, 2026

addedOutput schema / additionalProperties
```
Added value: +true
```

removedOutput schema / properties

Removed value: -{
-  "result": {
-    "title": "Result",
-    "type": "string"
-  }
-}

removedOutput schema / required
```
Removed value: -[
-  "result"
-]
```

changedOutput schema / title

Previous value: -"sassy_session_startOutput"New value: +"sassy_session_startDictOutput"

First observedv0.1.0Jul 31, 2026

TDQS

A5/5.0

Behavior5/5

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

Annotations already mark the tool as destructive and non-idempotent, and the description goes well beyond them: it discloses persistence, return fields, shell default behavior, refusal of live-name reuse and delete-interceptor commands, stderr merging, and the 50000-character tail buffer. This gives the agent a strong behavioral model before calling.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but every sentence earns its place: mutation flag, returns, defaults, refusal conditions, buffer behavior, and usage routing. No filler or repetition of schema data.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the output schema exists and annotations cover the mutation profile, the description supplies the remaining operational context: persistence, defaults, safety refusals, buffer limits, and relationships to sibling tools. An agent has everything needed to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden for parameter meaning. It explains name (unique live name, reuse refused), shell (defaults to host native shell with platform-specific options), and command (optionally runs immediately and can be intercepted if destructive).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: 'spawns a persistent terminal session under a unique name and returns its status, shell, and pid.' It clearly distinguishes this tool from sibling session tools like sassy_session_read, sassy_session_stop, and sassy_shell.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit usage guidance is provided: use this for long-running work such as dev servers or builds, use sassy_shell for one-shot commands, and stop sessions with sassy_session_stop when done. It also names the polling complement sassy_session_read, leaving no ambiguity about when to choose this tool.

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

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