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dangling_volumes

Read-only

Identify unreferenced Docker volumes and calculate reclaimable bytes to find prune candidates for reclaiming disk space.

Instructions

[READ] Dangling volumes (unreferenced) + reclaimable bytes — prune candidates.

Args: target: Target name from config; omit for the default.

Input Schema

NameRequiredDescriptionDefault
targetNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.6.0

TDQS

A3.9/5.0
Behavior3/5

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

Annotations provide readOnlyHint=true, so the safe-read profile is covered. The description adds that it reports reclaimable bytes, a useful data point. But it doesn't disclose whether the scan is heavy, whether it requires a running daemon, or how it interacts with the config target.

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?

Front-loaded with the [READ] tag and core purpose, then args. The single arg explanation is efficient, though the '[READ]' tag partly duplicates the readOnlyHint annotation.

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

Completeness4/5

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

For a one-parameter read-only tool with no output schema, the description covers the resource, the key output metric, and the sole parameter's semantics. Missing only an explicit pointer to prune_volumes as the follow-up action.

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 coverage is 0%, so the schema does not document the single target parameter at all. The description does explain that target is a 'Target name from config' and that omitting it yields the default, which compensates partially for the schema gap.

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 resource (dangling/unreferenced volumes) with the added metric (reclaimable bytes) and scope (prune candidates). Clearly distinguishes from siblings like list_volumes and prune_volumes by emphasizing 'unreferenced' and 'candidates'.

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?

The phrase 'prune candidates' implies this is the discovery step before prune_volumes, giving clear context. However, it does not explicitly name prune_volumes as the alternative or state when-not-to-use.

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