version: "1.0.0" name: cost-model description: Standardized cost-estimation framework for great-pm initiatives. Forces explicit LLM cost (across great-pm pipelines), human-equivalent comparison, infra delta, and time-to-ship. Output is parsable by /pm-burn and /pm-cost. great-pm version covers PM-side cost. when_to_use: | Apply when:

• /pm-cost is invoked to estimate a proposed initiative's cost
• /pm-burn is invoked to show great-pm's burn rate vs human-equivalent
• ai-product-strategist drafts a strategy with a cost claim
• ai-cost-optimizer authors a cost plan
• any great-pm report claims a savings ratio — must show methodology

allowed-tools: Read, Write

Cost model — make great-pm cost claims defensible

great-pm reports cost numbers on the board (via /pm-cost, /pm-burn, /pm-digest). Those numbers MUST be auditable. The classic mistake: a shiny "1000× human equivalent" claim that doesn't survive scrutiny. This skill defines the format and the discipline.

The 4-line cost section

Every great-pm initiative's cost section follows this exact template:

## Cost estimate
 
**LLM**: $<low>–<high> (<N> agent invocations × $<per-call avg>)
**Human equiv**: $<low>–<high> (<hours> × $<rate>/h)
**Infra delta**: $<low>–<high>/month
**Time to ship**: <hours> agent-time, <hours/days> wall-clock
 
> Methodology: <one-sentence rationale for each range>

Why this exact format?

Board parsers anchor on line-start "LLM" and "Human" labels. Mid-line references are ignored. Stick to the template — drift breaks the board.

How to estimate each line

LLM cost

For each great-pm agent that runs in the initiative, estimate:

• Prompt tokens = system prompt + injected context (PROJECT.md +

brain.md tail + HANDOFF.md, per SubagentStart hook) + agent-specific input

• Completion tokens = typical output for that agent type

Quick reference for the `opus` alias — great-pm's default model, which always resolves to the newest Opus (Opus 4.8 at time of writing): $5/M input, $25/M output (verified 2026-07-21 against Anthropic's price sheet — re-verify at each model release; the alias tracks new Opus versions automatically but pricing can change).

For claude-haiku-4-5 (lighter agents, $1/M in, $5/M out), divide by ~5.

Sum across the agents that actually fire for the initiative. Use PROJECT.md → archetype → which agents apply.

Human equiv

The human cost to do the SAME PM work without agents. "If I hired a senior PM to do this, how long would it take, at what rate?"

Estimate hours conservatively. A discovery brief great-pm produces in 15 min might take a senior PM 4–8 hours (interviews, synthesis, write-up). A pricing plan great-pm drafts in 20 min might take a pricing consultant 20–40 hours of work spread over 2 weeks.

Infra delta

Only count what's new for this initiative. Examples:

• New event tracking in product analytics → cost of analytics platform incremental usage
• New AI inference for a feature → tied to ai-cost-optimizer's per-action cost
• New monitoring dashboards → typically noise (don't list)
• New domain (e.g. compliance audit) → if it triggers a new pen-test or

SOC2 review cost, list it

If it's < $50/month of incremental infra, write "infra delta: ~$0".

Time to ship

Two numbers — both useful:

• Agent-time: wall-clock of LLM calls in aggregate. Typically

30 min – 4 hours across a full initiative loop.

• Wall-clock: actual elapsed including human gates. Typically days

to weeks because of gate:strategy / gate:spec / gate:launch approval waits.

Sanity check before writing

Before committing the section, verify:

ratio = human_equiv / llm_cost

If ratio > 3000, something is wrong. (Threshold recalibrated 2026-07-21: earlier drafts used 3x-inflated Opus pricing; at the correct $5/$25 the same honest work legitimately shows ~3x higher ratios.) Common bugs:

Plausible range: 150× to 1,500× human equivalent is real at current Opus pricing. Beyond 1,500×, double-check the methodology.

Initiative-level cost gate (for high-burn initiatives)

For initiatives projected to cost > $50 of great-pm LLM spend, open a cost-aware gate. Use the template:

## /pm-cost forecast
 
| Stage | Agents fired | LLM cost | Human equiv |
|---|---|---|---|
| Discover | user-researcher + feedback-synth + market-analyst | $X | $Y |
| Strategize | product-strategist + pm-reviewer | $X | $Y |
| Prioritize | prioritization-analyst (+ tradeoff-arbiter) | $X | $Y |
| Define | spec-writer + spec-reviewer + metrics-architect | $X | $Y |
| Launch | launch-manager + gtm-strategist | $X | $Y |
| Measure | analytics-analyst + experiment-designer | $X | $Y |
| **Total** | | **$<sum>** | **$<sum>** |
 
Recommended cap per initiative loop: $<cap>
Cap-breach trigger: pause loop; route to human for approval.

Anti-patterns

❌ Round-number theatre. "$1 LLM | $10,000 human" — looks suspicious. Use realistic ranges: "$0.80–2.40 | $450–900".

❌ Single point estimates. Always a range. Single numbers hide uncertainty.

❌ No methodology line. Numbers without rationale are unverifiable.

❌ Hand-waved infra. "Some cost" is not a number. Either give $, or "infra: ~$0".

❌ Inflated savings ratio. A 5000× claim makes the whole report look like marketing. Stick to defensible math.

❌ Counting agent calls you didn't actually make. Cost forecasts should reflect agents that ACTUALLY fire, not all agents in the roster.

Example — good

## Cost estimate
 
**LLM**: $0.60–1.20 (full Discover→Strategy loop, ~8 agent calls @ $0.08–0.15)
**Human equiv**: $1,200–2,400 (8–16h × $150/h, senior PM)
**Infra delta**: ~$0 (uses existing Beads + great-pm; no new infra)
**Time to ship**: ~35min agent-time, ~3 days wall-clock (2 human gates)
 
> Methodology: 8 calls = user-researcher + feedback-synth + market-analyst
> + product-strategist + prioritization-analyst + pm-reviewer + spec-writer
> + spec-reviewer. Per-call cost from the Opus quick reference above. Human
> equivalent benchmarked against a 1-FTE senior PM doing equivalent
> discovery+strategy+spec work over 1 week.

Ratio = 1800 / 1.2 = 1,500×. High but defensible at current Opus pricing — the math is shown.

When great-pm agents consume this skill

References

• engineering's cost-model skill (engineering-side; this is the PM parallel)
• Anthropic Opus pricing via the opus alias (re-verify at each release)
• Standard PM-rate benchmarks: levels.fyi, RippleMatch, PM salary surveys

The honesty filter

If your cost claim says "1000× cheaper" without showing the math, it's marketing. If your math survives 5 minutes of scrutiny, it's analysis. great-pm's credibility depends on the latter.