A structured workflow for planning, documenting, and implementing software changes. TDD, or test-driven development, means writing tests before the implementation.

Use it to create development plans, update project documentation, define interfaces and API details, and implement changes with tests first.

It keeps project decisions and requirements recorded while work progresses, so planning, specifications, implementation, and tests do not drift apart.

psi — Skill for Claude Code and Codex by siviter-xyz

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.

Any agent

npx skills add siviter-xyz/dot-agent --skill psi

Clone the repo

git clone --depth 1 https://github.com/siviter-xyz/dot-agent

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/siviter-xyz/dot-agent/psi/github.svg)](https://agentmods.dev/skills/siviter-xyz/dot-agent/psi)

Your own site

<a href="https://agentmods.dev/skills/siviter-xyz/dot-agent/psi"><img src="https://agentmods.dev/badge/skills/siviter-xyz/dot-agent/psi/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/siviter-xyz/dot-agent/psi"><img src="https://agentmods.dev/badge/skills/siviter-xyz/dot-agent/psi.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 668 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00047	$0.00668
Opus 5	$0.00023	$0.00334
Sonnet 5	$0.00009	$0.00134
Haiku 4.5	$0.00005	$0.00067

Measured 9d ago against content hash b9e814607af1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

psi 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 9d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/get-plan-path.js, scripts/get-research-path.js, scripts/show-plan-location.js), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/psi/SKILL.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PSI - Plan Spec Implement

Structured workflow for planning, specifying, and implementing changes with documentation-first approach.

When to Use

Only use when:

Explicitly directed by the user
Mentioned in project AGENTS.md file

Do not use automatically - this is an opt-in workflow, not a default.

Core Workflow

Plan → Spec → Implement

Phases are independent - you can start with any phase, but all must ensure documentation stays up-to-date.

Key Principles

Ephemeral planning - Plans stored in ~/.dot-agent/ (not committed)
Documentation-first - Specs applied to project docs/READMEs/AGENTS.md
Test-first implementation - Tests for docs/user journeys before code
Design/review embedded - Design and review integrated into Plan/Spec phases
Phase independence - Each phase can work standalone, all update docs

Phase Overview

Plan Phase

Generates detailed plans in ~/.dot-agent/repo/YYYY-MM-work-name.plan.md
Research stored in ~/.dot-agent/working-dir/repo/YYYY-MM-work-name.research.md
Embeds design considerations
Includes review before proceeding

Spec Phase

Generates specs for: API schemas, interfaces, DTOs, database models, config, env vars, architecture, user journeys, package structure, tech choices
Embeds design considerations
Reviews specs before applying
Applies to: docs/, README.md files, AGENTS.md files

Implement Phase

Test-first: tests for docs/user journeys before code
CI verification: verify types, tests, lint pass before committing
Atomic commits: group related changes with tests
Updates docs, README.md, AGENTS.md as code evolves
Can work independently if specs exist in docs

Research Management

Detects phrases like:

"looking at your research" → Loads research file
"refine your research" → Updates research file, narrows focus

Documentation Structure

README.md: Aim for < 1000 lines (not hard rule), can be longer if needed
AGENTS.md: < 200 lines, inline at root/packages/modules/code level
docs/: Architecture, roadmap, tech-choices, setup/, user-journeys/, design/

Read the full file on GitHub · 76 lines

Files

What ships with it

12 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

9d ago First seen · 76 lines · 47 tokens per session scan A b9e814607af1

Subscribe to this mod's changes

psi is a skill published in the GitHub repository siviter-xyz/dot-agent (21 stars, last pushed 5mo ago), licensed MIT. It adds 47 tokens to every session and 668 once invoked, about $0.0002 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.

Planning TDD Testing

psi