perseus

perseus_drift

Read-only

Detect drift between predicted and actual tool usage patterns using the Pythia oracle. Identifies inconsistencies after configuration changes or when behavior seems off.

Instructions

Detect drift between predicted and actual tool usage patterns via the Pythia oracle. Use when tool behavior seems off or after config changes. For workspace hygiene checks, prefer perseus_health. Read-only; returns a markdown drift report.

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": "perseus_drift"
  }
}

Input Schema

Name	Required	Description	Default
`args`	No	Arguments for @drift directive

Output Schema

Name	Required	Description	Default
`rendered`	No	Resolved directive output as markdown

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.0.10Jun 27, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "rendered": {
+      "description": "Resolved directive output as markdown",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

First observedv0.1.0May 27, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already indicate readOnlyHint=true; description adds that it is 'Read-only' and 'returns a markdown drift report,' providing output format information beyond annotations.

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 sentences with no wasted words. Information is front-loaded: purpose, usage, alternative, behavior, output type. Compact and efficient.

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 simple read-only tool with one optional parameter and an output schema, the description adequately covers purpose, usage, behavior, and output format. No gaps identified.

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 100% for the single parameter 'args,' with description 'Arguments for @drift directive.' The tool description does not add further semantics beyond the schema, so baseline 3 is appropriate.

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 clearly states 'Detect drift between predicted and actual tool usage patterns via the Pythia oracle,' specifying the action and resource. It distinguishes from sibling tool perseus_health by noting a different use case for workspace hygiene checks.

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

Usage Guidelines5/5

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

Explicit guidance on when to use ('when tool behavior seems off or after config changes') and when not to use ('For workspace hygiene checks, prefer perseus_health'), providing clear context and alternatives.

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