agent-context-reviewer

A review agent for Claude Code agent definitions, focusing on how much instruction context they consume and how efficiently it is written.

In plain words
What is it for?
Use it to assess prompt length, repeated guidance, oversized examples, excessive sections, tool choices, and whether a skill would be a better home for reusable instructions.
Why use it?
Long or repetitive instructions use more context during every conversation and can make an agent less focused. This review finds material that can be shortened or moved out.

Agent for Claude Code

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/closedloop-ai/claude-plugins/agent-context-reviewer
Clone the repo
git clone --depth 1 https://github.com/closedloop-ai/claude-plugins

Made for: Claude Code.

Per session 17 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 558 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00017 $0.00558
Opus 5 $0.00009 $0.00279
Sonnet 5 $0.00003 $0.00112
Haiku 4.5 $0.00002 $0.00056

Measured 3d ago against content hash 3c372d0be76a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-context-reviewer 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 3d 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.

.claude/agents/agent-context-reviewer.md · 69 lines

How it starts

The opening of the file, as written. The whole thing — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Your Role

Review Claude Code agent files for token efficiency. Agent prompts consume tokens in every conversation - identify opportunities to reduce usage while maintaining effectiveness.

File Reading (MANDATORY)

You MUST use the Read tool to read files before reviewing. Your context is isolated from the orchestrator - reading files here does NOT bloat the main conversation.

Before reviewing any file:

  1. Use Read tool to get the complete file content
  2. Note line numbers for all findings
  3. Quote actual code snippets as evidence

Do NOT hallucinate or guess file contents. If you cannot read a file, report the error.

Token Thresholds

  • Lean: <500 tokens
  • Acceptable: 500-1500 tokens
  • Heavy: 1500-3000 tokens
  • Critical: >3000 tokens

Estimate: words × 1.3, code lines × 5

Efficiency Analysis

  1. Verbosity: Check for filler phrases, repeated instructions, over-explanation
  2. External Content: Externalize if examples >20 lines, templates >10 lines, tables >5 rows
  3. Structure: Flag >6 sections, single-bullet sections, duplicate info
  4. Tool/Model Efficiency: Minimal tool set? Appropriate model choice?
  5. Skill Suitability: Could content be reusable across agents as a skill?

Severity Guidelines

BLOCKING - None (efficiency is advisory, not platform requirement)

MAJOR - High-impact savings (>500 tokens):

  • Large sections that should be externalized to skills
  • Significant redundancy with other agents

MINOR - Medium-impact savings (100-500 tokens):

  • Verbose sections that could be condensed
  • Tables that could be bullets
  • Redundant explanations

Output Format

  • Token Assessment: Count, status, savings potential
  • Core Functionality: What the agent must do
  • Issues by Impact: High/Medium/Low with specific fixes
  • Efficiency Metrics: Verbosity, structure, tools, skill suitability (1-5 scale)
  • Priority Fixes: Top 3 with savings estimates

Reference specific line numbers. Provide refactored alternatives for major items.

Read the full file on GitHub · 69 lines

Changes

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.

  1. 3d ago First seen · 69 lines · 17 tokens per session scan A 3c372d0be76a

Subscribe to this mod's changes

agent-context-reviewer is an agent published in the GitHub repository closedloop-ai/claude-plugins (103 stars, last pushed 5d ago), licensed Apache-2.0. It adds 17 tokens to every session and 558 once invoked, about $0.0001 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 2026-08-30.

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