echo

A response rule that checks whether the user has already settled a substantive question in an earlier conversation before answering it.

In plain words
What is it for?
Use it for recommendations, disputed approaches, and other questions involving a choice or evolving view; skip it for greetings, simple commands, and clearly new operational questions.
Why use it?
It avoids repeating decisions and lets the agent point out earlier conclusions when they are still relevant.

Skill for Claude CodeCodex

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 skills/ghostwright/phantom/echo
Any agent
npx skills add ghostwright/phantom --skill echo
Clone the repo
git clone --depth 1 https://github.com/ghostwright/phantom

Made for: Claude Code, Codex.

Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 969 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 $0.00022 $0.00969
Opus 5 $0.00011 $0.00485
Sonnet 5 $0.00004 $0.00194
Haiku 4.5 $0.00002 $0.00097

Measured yesterday against content hash 93b8741c0a5f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

echo 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 yesterday.

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.

skills-builtin/echo/SKILL.md · 77 lines

How it starts

The opening of the file, as written. The whole thing — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Echo: the prior-answer surfacer

Goal

Respect the user's past thinking. Before deriving a new answer to a substantive question, check whether the user already resolved this question weeks or months ago. If yes, surface the prior answer inline and ask whether anything has changed. If no, proceed to answer normally without mentioning that you looked.

The user should feel like you remember what they already decided, not like you are doing paperwork.

Steps

1. Classify the question

Determine whether the question is substantive. Skip if:

  • It is a greeting or acknowledgment ("hey", "thanks", "got it").
  • It is an operational query ("are you online", "what time is it", "are you working on X").
  • It is an imperative with no open decision ("send this to Anna", "delete that file").
  • It is clearly a first-time question with no prior context ("what does this error mean in this new log line").

Proceed if:

  • The user is asking for a recommendation or opinion.
  • The user is asking "what did we decide" or "what is the right way".
  • The user is weighing options on something they have discussed before.
  • The user is asking a question that sounds like it could have been asked before.

Success criteria: you have a yes or no on whether to run the echo check. If no, do not call the search tool at all.

2. Search memory for prior answers

Call mcp__phantom-reflective__phantom_memory_search with query: "<the user's question in your own words>", memory_type: "all", limit: 5. The query should be a restatement of the semantic intent, not a literal copy of the user's words.

Success criteria: you have a list of 0-5 hits with similarity scores.

3. Judge the match

Examine the top hit. It is a strong match if all of these hold:

  • Similarity score is above 0.80 if the tool returns one.
  • The hit is at least 3 days old.
  • The hit actually addresses the same question, not just the same keywords.
  • You can clearly see what the prior conclusion was.

If the top hit is NOT a strong match, proceed to answer the question normally from scratch. Do not mention the echo check to the user.

Read the full file on GitHub · 77 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. yesterday First seen · 77 lines · 22 tokens per session scan A 93b8741c0a5f

Subscribe to this mod's changes

echo is a skill published in the GitHub repository ghostwright/phantom (1,463 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 22 tokens to every session and 969 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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