compaction-mcp

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Fetch offloaded content

offload_fetch

Retrieve full or partial content from a stored blob, using line slices to fetch only needed data and minimize context window usage.

Instructions

Retrieve a blob's full content, or a 1-indexed inclusive line slice. Use the smallest slice that answers the question to keep the window small.

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": {
      "handle": "<handle>"
    },
    "name": "offload_fetch"
  }
}

Input Schema

Name	Required	Description	Default
`handle`	Yes
`endLine`	No
`startLine`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 7, 2026

TDQS

A3.7/5.0

Behavior4/5

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

With no annotations, the description carries the full burden. It discloses key behavioral traits: the slice is 1-indexed and inclusive, and the tool can return full content or a slice. This adds valuable context beyond the schema, though it does not mention error handling or side effects.

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 two sentences, front-loaded with the core function ('Retrieve a blob's full content, or a 1-indexed inclusive line slice'), followed by practical guidance. No wasted words.

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

Completeness3/5

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

For a simple fetch tool with no output schema and no annotations, the description covers the basic retrieval behavior and slicing guidance. However, it lacks information about return format, error conditions, and how it differs from read_offloaded, leaving some context gaps.

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?

Schema description coverage is 0%, so the description must compensate. It explains that startLine/endLine define a 1-indexed inclusive slice and that handle refers to a blob. However, it does not clarify that startLine and endLine are optional, must be used together, or any constraints like startLine <= endLine.

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

Purpose4/5

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

The description clearly states the tool retrieves a blob's full content or a line slice, using a specific verb and resource. However, it does not differentiate from the sibling tool 'read_offloaded', which likely serves a similar purpose.

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

Usage Guidelines3/5

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

The description advises using the smallest slice to keep the window small, which is useful usage guidance for parameter selection. However, it does not explicitly state when to use this tool versus alternatives like read_offloaded or offload_store, so the guidance is implied rather than explicit.

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