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skill-cost-projections · octo · Flowy
Project remaining workflow cost from per-phase averages — warns on budget ceiling overruns
One skill from octo .
$ npx -y skills add nyldn/claude-octopus --skill skill-cost-projections --agent claude-codeInstalls just this skill. Get the whole plugin for auto-invocation.
⚡ How it fires
How this skill gets triggered: by you, by Claude, or both.
Fires itself Claude auto-loads it when your prompt matches the work. You can call it Invoke it directly when you want it. Slash command /skill-cost-projections👁️ Context preview
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Project remaining workflow cost from per-phase averages — warns on budget ceiling overruns </> SKILL.md
skill-cost-projections.SKILL.md
---
name : skill-cost-projections
effort : low
aliases:
- cost-projections
- cost-forecast
- budget-projection
description : "Project remaining workflow cost from per-phase averages — warns on budget ceiling overruns"
trigger : |
AUTOMATICALLY ACTIVATE when user asks about workflow costs:
- "cost projection", "estimate remaining cost"
- "budget forecast", "how much will this cost"
- "project cost", "cost estimate", "spending forecast"
- "what's the cost so far", "am I over budget"
DO NOT activate for:
- General pricing questions about API models
- One-time cost lookups unrelated to a running workflow
- Provider availability or configuration questions
paths:
- "**/.claude-octopus/**"
- "**/analytics/**"
---
# Cost Projections Skill
## Overview
Projects remaining workflow cost based on per-phase averages from completed work. Displays cost data in the HUD/statusline and warns when projected totals exceed a configured budget ceiling.
**Minimum data requirement:** Needs **2+ completed steps** before projecting. With fewer than 2 data points, the average is unreliable — display actual spend only and skip projection.
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---
## Step 1: Collect Completed Phase Costs
Read cost data from `~/.claude-octopus/metrics/` or from metrics-tracker.sh output. Each completed phase/step should have an associated cost entry.
```bash
# Read metrics from the session metrics directory
METRICS_DIR="$HOME/.claude-octopus/metrics"
SESSION_METRICS="$METRICS_DIR/session-$(date +%Y%m%d).jsonl"
# Each line contains: {"phase": "discover", "cost": 0.42, "tokens_in": 12000, "tokens_out": 3400, "timestamp": "..."}
# Sum costs from completed steps
completed_costs=$(jq -s '[.[].cost]' "$SESSION_METRICS")
completed_count=$(jq -s 'length' "$SESSION_METRICS")
total_spent=$(jq -s '[.[].cost] | add' "$SESSION_METRICS")
```
**Data sources (in priority order):**
1. `~/.claude-octopus/metrics/session-*.jsonl` — structured per-phase cost entries
2. `metrics-tracker.sh` output — fallback for legacy sessions
3. HUD accumulated cost counters — last resort
If fewer than 2 completed steps are available, display only actual spend:
```
💰 Spent: $0.42 (1 step complete — need 2+ for projection)
```
---
## Step 2: Compute Average Cost Per Step
Calculate the mean cost across all completed steps.
```bash
avg_cost=$(echo "$total_spent / $completed_count" | bc -l)
```
**Formula:**
```
avg_cost = total_cost / completed_steps
```
**Example:** If 3 steps cost $0.30, $0.50, $0.40 → avg = $1.20 / 3 = $0.40/step
---
## Step 3: Project Remaining Cost
Multiply the average cost per step by the number of remaining steps.
```bash
remaining_steps=$((total_steps - completed_count))
projected_remaining=$(echo "$avg_cost * $remaining_steps" | bc -l)
projected_total=$(echo "$total_spent + $projected_remaining" | bc -l)
```
**Formula:**
```
projected_remaining = avg_cost × remaining_steps
projected_total = total_spent + projected_remaining
```
**Step counts by workflow type:**
| Workflow | Total Steps | Example Phases |
|----------|-------------|----------------|
| embrace | 4 | Discover, Define, Develop, Deliver |
| research | 3-7 | Per-agent probe count |
| review | 3 | Fleet, Verifier, Synthesis |
| debate | 3 | Opening, Rebuttal, Synthesis |
---
## Step 4: Display in HUD
Format the cost projection for the HUD/statusline display.
**Standard display:**
```
💰 Spent: $2.40 | Est. remaining: $3.60 | Total: ~$6.00
```
**Format rules:**
- All dollar amounts to 2 decimal places
- Projected total prefixed with `~` to indicate estimate
- Use `💰` prefix for the cost line
- Show in a single compact line for statusline integration
**When insufficient data (< 2 steps):**
```
💰 Spent: $0.42 (need 2+ steps for projection)
```
**Integration:** This display line is emitted by the octopus-hud hook and rendered in the statusline alongside phase progress and provider status.
---
## Step 5: Budget Ceiling Warning
If the `OCTO_BUDGET_CEILING` environment variable is set, compare the projected total against it and warn on overrun.
```bash
if [[ -n "${OCTO_BUDGET_CEILING:-}" ]]; then
ceiling="$OCTO_BUDGET_CEILING"
if (( $(echo "$projected_total > $ceiling" | bc -l) )); then
overage=$(echo "$projected_total - $ceiling" | bc -l)
echo "⚠️ Budget ceiling: \$$ceiling — projected to exceed by \$$overage"
fi
fi
```
**Display when over budget:**
```
💰 Spent: $2.40 | Est. remaining: $3.60 | Total: ~$6.00
⚠️ Budget ceiling: $5.00 — projected to exceed by $1.00
```
**Display when within budget:**
```
💰 Spent: $2.40 | Est. remaining: $3.60 | Total: ~$6.00
✅ Within budget ceiling: $10.00
```
**Note:** `OCTO_BUDGET_CEILING` is optional. When unset, no ceiling check is performed.
---
## Step 6: Profile Suggestion
If the projected total is high relative to the task, suggest switching to the budget profile to reduce costs.
```bash
# Suggest budget profile when projected total exceeds $5.00 (configurable)
COST_THRESHOLD="${OCTO_COST_THRESHOLD:-5.00}"
if (( $(echo "$projected_total > $COST_THRESHOLD" | bc -l) )); then
echo "💡 Tip: Switch to OCTO_PROFILE=budget to reduce costs"
fi
```
**Display:**
```
💰 Spent: $2.40 | Est. remaining: $3.60 | Total: ~$6.00
💡 Tip: Switch to OCTO_PROFILE=budget to reduce costs
```
The budget profile (`OCTO_PROFILE=budget`) routes to cheaper models and reduces agent count to minimize spend.
---
## Complete Display Examples
**Normal — within budget, moderate cost:**
```
💰 Spent: $2.40 | Est. remaining: $3.60 | Total: ~$6.00
```
**Over budget ceiling:**
```
💰 Spent: $2.40 | Est. remaining: $3.60 | Total: ~$6.00
⚠️ Budget ceiling: $5.00 — projected to exceed by $1.00
💡 Tip: Switch to OCTO_PROFILE=budget to reduce costs
```
**Early in workflow (insufficient data):**
```
💰 Spent: $0.42 (need 2+ steps for projection)
```
**Low cost — no warnings:**
```
💰 Spent: $0.80 | Est. remaining: $0.80 | Total: ~$1.60
```
---
## Integration
### With octopus-hud hook
The cost projection line is rendered as part of the HUD statusline output, updated after each phase completes.
### With metrics-tracker.sh
Reads per-phase cost data written by the metrics tracker. Each completed phase logs cost, token counts, and provider details.
### With OCTO_PROFILE
When `OCTO_PROFILE=budget` is active, the projection accounts for reduced per-step costs from cheaper model routing.
---
## Error Handling
**No metrics directory:**
```
💰 Cost projection unavailable — no metrics data found
```
**Corrupted metrics data:**
Skip malformed entries and project from valid data only. If no valid entries remain, show unavailable message.
**Zero remaining steps:**
When all steps are complete, show final total only:
```
💰 Final cost: $4.80 (4 steps)
```
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