alterlab-mcp-server

Cancel Crawl

alterlab_crawl_cancel

DestructiveIdempotent

Cancels an ongoing crawl and refunds unused pre-debited credits. Already-scraped pages stay available via status checks, but cancelled crawls cannot be resumed.

Instructions

Cancel an ongoing crawl and refund unused pre-debited credits. Already-scraped pages are kept and available via alterlab_crawl_status. Cancelled crawls cannot be resumed.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "crawl_id": "<crawl_id>"
    },
    "name": "alterlab_crawl_cancel"
  }
}

Input Schema

Name	Required	Description	Default
`crawl_id`	Yes	Crawl ID to cancel

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.5.0Jun 12, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already flag destructiveHint=true, but the description usefully bounds that destructiveness: partial results survive, credits are refunded, and the operation is irreversible in the sense that the crawl cannot be resumed. It leaves out what happens with an invalid or already-completed crawl_id, but the post-condition disclosure is well beyond what annotations provide.

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?

Three short sentences, each carrying a distinct fact: the action, the side effects on data and credits, and the irreversibility. The primary action is front-loaded with no filler.

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?

For a one-parameter mutation with annotations and no output schema, the description supplies everything an agent needs: what is destroyed, what is preserved, what is refunded, and that the state is terminal.

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

Parameters3/5

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

The single parameter is fully documented in the schema (100% coverage) as "Crawl ID to cancel." The description adds no syntax, format, or sourcing guidance for crawl_id, so the schema carries the whole burden and the baseline of 3 applies.

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?

States a specific verb and resource ("Cancel an ongoing crawl") plus a second concrete effect (refund of unused pre-debited credits). This is unmistakably distinct from siblings like alterlab_crawl (start) and alterlab_crawl_status (inspect).

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

Usage Guidelines4/5

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

Implies the usage context clearly: this is the stop action for an in-flight crawl, and it names alterlab_crawl_status as the follow-up for retrieving kept pages. It does not explicitly state when-not-to-use or warn about calling it on a finished crawl, so it falls short of a full alternative-routing statement.

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