| name | cost-check |
| description | Generic cost estimation for IaC projects. Detects the IaC stack (Pulumi, Terraform) and compatible cost tool (finfocus, infracost), runs cost analysis, flags expensive resources, cost increases, and total cost against configurable thresholds. Produces a terminal summary and COST_CHECK.md report. Use when checking infrastructure costs, reviewing cost impact of changes, or enforcing budget thresholds in CI.
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| compatibility | Requires an IaC project (Pulumi.yaml or *.tf files). Enhanced with cost tools: finfocus (Pulumi), infracost (Terraform). Soft-fails with recommendations when no compatible tool is installed.
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Cost Check
Detect the IaC stack in the current directory, run a compatible cost
tool, and produce a cost report with flagged items.
Core principle: Orchestrate real cost tools — do not parse IaC
files directly or estimate prices manually.
Step 1: Detect IaC stack
Scan the current directory for IaC project files:
ls Pulumi.yaml 2>/dev/null && echo "pulumi: detected"
ls *.tf 2>/dev/null && echo "terraform: detected"
If no IaC files are found, stop and report:
"No IaC project detected in this directory."
For the full detection table, see references/tool-matrix.md.
Step 2: Detect cost tool
For each detected IaC stack, check if a compatible cost tool is
installed:
command -v finfocus 2>/dev/null && echo "finfocus: available"
command -v infracost 2>/dev/null && echo "infracost: available"
If no compatible tool is found for a detected stack, soft-fail:
report which IaC stack was detected and recommend the appropriate
tool. Do not prescribe install commands — link to the tool's own
documentation. See references/tool-matrix.md for recommendations.
If the only available tool is incompatible with the detected stack
(e.g., infracost found but project is Pulumi), treat the same as
no tool found.
Step 3: Load thresholds
Check for .cost-check.yml in the project root. If present, read
threshold overrides. If absent, use defaults from
references/default-thresholds.md:
- resource: $100/mo (flag individual resources above)
- increase: $50/mo (flag cost increases above)
- increase_pct: 20% (flag cost increase percentage above)
- total: $1000/mo (flag total cost above)
Step 4: Read baseline
If a previous COST_CHECK.md exists in the project root, read the
total monthly cost from it. This serves as the baseline for delta
comparison. If no previous report exists, skip delta flagging.
Step 5: Run cost tool
Run the compatible cost tool for each detected IaC stack. See
references/tool-parsers.md for per-tool invocation and parsing
instructions.
Capture the full output. Extract into the normalized structure:
- Total projected monthly cost
- Per-stack/workspace breakdown
- Per-resource-type grouping within each stack
- Individual resource costs
Step 6: Flag items
Apply thresholds to the normalized cost data:
- Expensive resources — flag any resource with monthly cost
above the resource threshold
- Cost increase — if a baseline exists, flag if the total cost
increase exceeds the increase threshold OR the increase percentage
exceeds the increase_pct threshold
- Total cost — flag if total projected cost across all stacks
exceeds the total threshold
Step 7: Terminal summary
Print the results immediately:
- IaC stack and cost tool used
- Per-stack total with resource type breakdown
- Flagged items with threshold that triggered the flag
- Delta from baseline (if baseline exists)
- Total across all stacks
Step 8: Generate COST_CHECK.md
Write the report to the project root using the template in
references/report-template.md. Include all sections: summary,
stack breakdown, flagged items, thresholds used, and tool info.
Run markdownlint on the generated file.
Step 9: Present results
Show the user:
- Total projected cost across all stacks
- Number of flagged items by category
- Top flagged items with costs
- Delta from previous check (if baseline existed)
- Ask if they want to adjust thresholds or investigate specific items
