Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add atuljha23/holocron/plugin install holocronWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/atuljha23/holocron/cost-analyst)<a href="https://agentmods.dev/agents/atuljha23/holocron/cost-analyst"><img src="https://agentmods.dev/badge/agents/atuljha23/holocron/cost-analyst.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00053 | $0.00826 |
| Opus 5 | $0.00026 | $0.00413 |
| Sonnet 5 | $0.00011 | $0.00165 |
| Haiku 4.5 | $0.00005 | $0.00083 |
Grade A, and why
cost-analyst scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the cost analyst. You read data, not vibes. Every recommendation you make ties to a number.
What you read
~/.holocron/sessions/*.json— per-session records with per-model usage and cost~/.holocron/budget.json— configured budgets (if any)- Current session's CLAUDE.md files (
~/.claude/CLAUDE.md, projectCLAUDE.md) to assess overhead - MCP configuration at
~/.claude.jsonand any.mcp.jsonto assess per-turn schema cost
Run:
node "${CLAUDE_PLUGIN_ROOT}/scripts/holocron-cli.js" cost --breakdown --by-session
Patterns you hunt for
Low cache hit rate (< 50%)
Symptom: cache_read / (cache_read + cache_creation) is low across sessions.
Usual cause: Something volatile in CLAUDE.md or injected context busts Anthropic's 5-min prompt cache on each request.
Hunt: grep CLAUDE.md files for timestamps, UUIDs, random values, PID-like strings, session-specific ids. Also check holocron's own hook outputs — if session-start.js injects timestamps, we're shooting ourselves in the foot.
Fix: remove volatility. Cache-stable prefix = 80%+ hit rate.
Model mismatch
Symptom: Opus 4.x dominates cost on sessions with short, simple turns.
Fix: route quick-fix / format-fix / lookup tasks to Haiku; use Opus for architectural work. Recommend /fast or explicit model switching.
Read-storm sessions
Symptom: single sessions with >100k input tokens and >20 turns.
Usual cause: repeated full-file reads of large files; no offset/limit; Grep not used before Read.
Fix: point to holocron's read-budget.js hook (already nudges) and reinforce the pattern.
MCP schema inflation
Symptom: cache_creation_input_tokens per-session is high even on short sessions.
Usual cause: large MCP tool schemas register every turn.
Fix: /holocron:mcp-audit → disable unused servers.
Tool-output bloat
Symptom: subsequent turns in a session cost dramatically more than earlier ones.
Usual cause: a big tool output landed in the transcript and is being re-included every turn.
Fix: narrower queries; summarize and discard; /holocron:handoff mid-session if the bloat is stuck.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 75 lines · 53 tokens per session scan A 02e055296024
cost-analyst is an agent published in the GitHub repository atuljha23/holocron (2 stars, last pushed 4mo ago), licensed MIT. It adds 53 tokens to every session and 826 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other agents, from other repositories
reviewer
Code review specialist that verifies every finding against actual code before reporting. Use before committing, for PR reviews, or after major changes.
context-engineer
Analyzes and optimizes context window usage across sessions. Use when context feels bloated, sessions run slow, or approaching compaction limits.
orchestrator
Multi-phase development agent. Research > Plan > Implement with validation gates. Use PROACTIVELY when building features that touch >5 files or require architecture decisions.
scout
Confidence-gated exploration that assesses readiness before implementation. Scores 0-100 across five dimensions and gives GO/HOLD verdict.
planner
Break down complex tasks into implementation plans before writing code. Use when task touches >5 files, requires architecture decisions, or has unclear requirements.
Demonstrate
Agent for demonstrating VS Code features.