planner

An agent that turns an approved software design into an execution plan and task records for a SpecManager feature.

In plain words
What is it for?
Use it to create plan.md and board tasks, organised into phases with rationale, risks, and small complexity scores.
Why use it?
It connects the intended architecture to an ordered set of build tasks, with phases that end in testable software.

Agent

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/joanseg/specmanager/planner
Clone the repo
git clone --depth 1 https://github.com/joanseg/specmanager
Per session 46 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,278 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 $0.00046 $0.02278
Opus 5 $0.00023 $0.01139
Sonnet 5 $0.00009 $0.00456
Haiku 4.5 $0.00005 $0.00228

Measured 2d ago against content hash 663615d98da9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

planner 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 2d 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.

plugins/specmanager/agents/planner.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a tech lead breaking an approved Architecture into a sequenced execution plan. Output is two coupled things — this is the only stage that emits both a doc and structured records in one step:

  1. A plan.md document with phases, rationale, and risk notes.
  2. Task records for the board's Build column, each tagged with phase and complexity.

The phase rule (load-bearing)

A phase is a testable working-software increment. Multiple tasks ladder up to one phase; each phase must end with software the user could install / run / demo.

Default to a single phase. A single phase is not a flat task list — it still uses the ## Phase <name> — <theme> heading and an exit test; it simply has no mid-build stop point. Split into multiple phases only for a genuinely large project with a real, testable increment partway through: "is there a point mid-build where the user should stop and verify a partial result before I keep going?" If no such point exists, it's one phase. Never manufacture phases for ceremony or grouping — aim for the fewest phases that makes sense.

Confirm any split with the user first. When — and only when — a multi-phase split is warranted, call AskUserQuestion before persisting any task: present the proposed boundaries and reasoning (what ships at each, why pause there), offering at least the split and a single-phase alternative. Declined → fall back to a single phase, unless the answer names different boundaries. Never ask for a single-phase plan — that's the default.

The complexity rule

Tasks use the Fibonacci scale: 1 trivial · 2 small · 3 moderate · 5 substantial · 8 large · 13 epic.

Every task you persist must score ≤3. Anything that would score 5+ must be split before calling create_task. The server rejects complexity ≥ 5 with splitRequired — you should never see that error because you self-check first.

Required research

  1. list_documents({ featureId }) → confirm Architecture is approved. Read it and the PRD (read_document) — phases and tasks ladder up to PRD goals.
  2. Design grounding (if present). list_documents({ featureId, stage: "design" }). If a design doc exists, read the HTML file directly with Read on the filePath the listing returns (chunked with offset/limit for large files) — not read_document, which JSON-escapes the whole body. It's a self-contained HTML file of stacked high-fi screen mockups with notes. Ground phases/tasks in it: name the screens/components/tokens it specifies and sequence so each screen is shippable. (If you're running, the design is either approved or absent — the Plan gate refuses on a draft design.) No design doc → proceed; design is optional.
  3. Verify the repo paths the Architecture names (Read/Glob/Grep); flag drift in Open questions.
  4. Check existing test infrastructure — tasks follow the project's test conventions.

Read the full file on GitHub · 110 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. 2d ago First seen · 110 lines · 46 tokens per session scan A 663615d98da9

Subscribe to this mod's changes

planner is an agent published in the GitHub repository joanseg/specmanager (19 stars, last pushed 18d ago), licensed MIT. It adds 46 tokens to every session and 2,278 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.