hermes prompt-size Command — Complete Reference & Examples

Overview

hermes prompt-size reports the fixed prompt budget for a fresh session: the system prompt total, the skills index, memory, the user profile, and the tool-schema JSON. It runs fully offline — no API call is made — so you can check how much context window overhead a session will carry before you start it.

hermes prompt-size

Options

Option	Description
`--platform PLATFORM`	Platform to simulate (`cli`, `telegram`, `discord`, …). Default: `cli`
`--json`	Emit the breakdown as JSON

What It Reports

Component	Description
System prompt total	Total size of the fixed system prompt for a fresh session
Skills index	Summaries of all installed skills injected into the prompt
Memory	Memory context included in the prompt
User profile	Profile and preference context
Prompt tiers	Stable, context (AGENTS.md / cwd files), and volatile blocks
Tool schemas	JSON schemas for all enabled tools, plus a per-toolset breakdown

Common Scenarios

Checking the Default Budget

hermes prompt-size
# See the system prompt total and the largest blocks for the cli platform

Comparing Platforms

hermes prompt-size --platform telegram
# Telegram messages carry a different fixed overhead than cli sessions

Machine-Readable Output

hermes prompt-size --json
# Parse the breakdown with jq or your own tooling

Planning for a Smaller Model

hermes prompt-size
# If the total is close to a small model's context limit:
# - Disable unused tools
# - Remove unneeded skills
# - Trim memory context

Tips

The command runs entirely offline — no API calls, no cost
Use --platform to simulate different messaging platforms
Use --json when you need the breakdown in scripts or monitoring
The skills index and memory can dominate the fixed overhead — keep them lean
Pair with hermes status for the full runtime picture