scratch-unified-mcp

by blessed0x

Overview Schema Source Related Servers Discussions Admin

Python

Local

Sb3 Scratch Login

sb3_scratch_login

Authenticate a Node session with Scratch credentials to enable private project access and user-specific actions.

Instructions

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "sb3_scratch_login"
  }
}

Input Schema

Name	Required	Description	Default
`password`	No
`username`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 19, 2026

TDQS

C2.9/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions that the operation is 'proxied' and tied to the Node session, but does not explain side effects, whether existing authentication is replaced, persistence, or failure behavior.

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

Conciseness4/5

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

The description is a single front-loaded sentence with no filler. The parenthetical '(proxied)' is cryptic but does not add significant clutter.

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

Completeness2/5

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

Although an output schema exists and this is a superficially simple login tool, the description leaves important gaps: when login is required, what happens to the current session, what 'proxied' means, and how the optional parameters behave. An agent cannot confidently decide to invoke it based on this alone.

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

Parameters2/5

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

Schema description coverage is 0%, and the description does not mention username or password at all. The parameter names are self-evident as credentials, but the optional nature (both default to '') and any special login behavior are unexplained.

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 action ('Log in') and a clear target ('scratch.mit.edu') while also scoping the effect to 'the Node session.' This distinguishes it from sibling session tools like social_connect_session or social_verify_session, even without naming them explicitly.

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

Usage Guidelines2/5

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

The description gives no explicit guidance on when to call this tool, when not to, or which sibling session tool to prefer. 'For the Node session' implies a use context, but prerequisites and alternatives are left unstated.

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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