compaction-mcp

Overview Schema Source Related Servers Discussions Admin

Trim context (tier-1 prune)

context_trim

Eliminate low-value and duplicate tool outputs from the session to reduce context pressure, without an inference call. Works in store mode to maintain conversation efficiency.

Instructions

Remove low-value/duplicate tool output without an inference call. Store mode only.

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": "context_trim"
  }
}

Input Schema

Name	Required	Description	Default
`sessionId`	No
`dropToolOutputOlderThanTurns`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 7, 2026

TDQS

B3.2/5.0

Behavior3/5

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

With no annotations, the description bears the burden of behavioral disclosure. It discloses that the operation does not invoke inference and only works in store mode, which is useful. However, it does not explain side effects (e.g., irreversibility), what constitutes low-value/duplicate, or what happens if store mode is not active.

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 a single sentence of 11 words, front-loaded with the core action and key constraints. Every word earns its place; there is no filler or repetition. This is an example of efficient, well-structured writing.

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?

Despite the tool's simplicity, the description is incomplete given the absence of annotations and output schema. It lacks parameter explanations, usage conditions beyond 'store mode', and behavioral details. An agent would likely need clarification to invoke it correctly.

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 the parameters at all. The parameters 'sessionId' and 'dropToolOutputOlderThanTurns' are only self-descriptive by name, which may be insufficient for an agent to know how to set them correctly. The description offers no compensation for the lack of schema descriptions.

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 action ('Remove low-value/duplicate tool output') and adds specific constraints ('without an inference call', 'Store mode only'). It distinguishes itself from siblings like context_compact and context_clear by focusing on pruning specific tool output rather than compressing or clearing all context. However, the phrase 'Store mode only' is ambiguous without additional context.

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 implies usage for cleaning up low-value or duplicate tool output and restricts to store mode. It does not explicitly name alternatives or state when not to use this tool. The sibling list suggests related tools (context_compact, context_clear), but no comparison is provided.

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