Skills dimensional-analysis
Annotates codebases with dimensional analysis comments documenting units, dimensions, and decimal scaling. Use when someone asks to annotate units in a codebase, perform a dimensional analysis, or find vulnerabilities in a DeFi protocol, offchain code, or other blockchain-related codebase with arithmetic. Prevents dimensional mismatches and catches formula bugs early.
git clone https://github.com/trailofbits/skills
T=$(mktemp -d) && git clone --depth=1 https://github.com/trailofbits/skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/plugins/dimensional-analysis/skills/dimensional-analysis" ~/.claude/skills/trailofbits-skills-dimensional-analysis && rm -rf "$T"
plugins/dimensional-analysis/skills/dimensional-analysis/SKILL.mdDimensional Analysis Skill
This skill orchestrates a dimensional-analysis pipeline for codebases that perform numeric computations with mixed units, precisions, or scaling factors. The main skill context is a workflow controller only: it delegates scanning, vocabulary discovery, annotation, propagation, and validation to specialized subagents, then manages batching, persistence, retries, coverage gates, and final reporting.
When to Use
- Annotating a codebase with unit/dimension comments (e.g.,
,D18{tok}
)D27{UoA/tok} - Performing dimensional analysis on DeFi protocols, financial code, or scientific computations
- Hunting for arithmetic bugs caused by unit mismatches, missing scaling, or precision loss
- Auditing codebases with mixed decimal precisions or fixed-point arithmetic
When NOT to Use
- Codebases with no numeric arithmetic or unit conversions — there is nothing to annotate
- Pure integer counting logic (loop indices, array lengths) with no physical or financial dimensions
- When you only need a quick spot-check of a single formula — read the code directly instead of running the full pipeline
Execution Mode
This skill runs in one mode only:
full-auto.
This is a workflow-based skill that delegates step-specific work to specialized agents via the Task tool. You orchestrate the overall process, manage coverage and state persistence, and ensure that every in-scope file is processed through each step of the pipeline.
- Always run the full pipeline in this order: Step 1 -> Step 2 -> Step 3 -> Step 4.
- The main skill context must not perform repository-wide dimensional analysis, annotation, propagation, or bug validation itself when a dedicated subagent exists for that step.
- The main skill context may inspect artifacts, manifests, and subagent outputs only as needed to route work, build prompts, persist state, and determine completion.
- Any mode argument provided by the caller is ignored.
- Report all results at the end in a single summary.
When you start a step, report it:
Starting Step: Step {n}
Scope and Coverage Guarantees
This skill must audit all in-scope arithmetic files, including large repositories.
- In-scope files are defined by Step 1 scanner output (
array), across all priority tiers (CRITICAL, HIGH, MEDIUM, LOW).files - If Step 1 narrows inputs for vocabulary discovery (for example, CRITICAL/HIGH only), that narrowing applies to discovery only. It never reduces annotation or validation scope.
persists the in-scope file manifest toarithmetic-scanner
in the project root, and that manifest is the source of truth for Steps 2-4.DIMENSIONAL_SCOPE.json- A file is considered fully covered only when all three statuses are present:
: anchor annotation completed (or explicit no-anchor result)step2
: propagation completed (or explicit no-propagation result)step3
: validation completedstep4
persists the discovered dimensional vocabulary todimension-discoverer
in the project root for reuse by later steps and future runs.DIMENSIONAL_UNITS.md- When a file ends in a terminal
state, persist the blocking reason and retry count inBLOCKED
and reflect the same file inDIMENSIONAL_SCOPE.json
.coverage.unprocessed_files - Do not finish while any in-scope file remains unprocessed in any step.
Delegation Contract
owns repository scanning, arithmetic-file prioritization, and writingarithmetic-scanner
.DIMENSIONAL_SCOPE.json
owns dimensional vocabulary discovery, unit inference, and writingdimension-discoverer
.DIMENSIONAL_UNITS.md
owns annotation format decisions, anchor-point edits, and comment-writing behavior.dimension-annotator
owns propagation logic, inferred annotations, and mismatch reporting during tracing.dimension-propagator
owns bug detection, red-flag evaluation, rationalization rejection, and confirmation or refutation of propagated mismatches.dimension-validator- The main skill context must not substitute its own dimensional reasoning for skipped or unlaunched subagents. If a step requires specialized reasoning, launch the corresponding subagent.
- Use reference files as subagent support material. Pass them to the relevant step in prompts instead of treating them as instructions for the main skill context.
Workflow
Follow these sections in order. Do not advance until the current step satisfies its completion gate.
Shared Orchestration Rules
andDIMENSIONAL_SCOPE.json
live in the project root.DIMENSIONAL_UNITS.md- The main skill context verifies Step 1 artifacts but does not write either Step 1 artifact itself.
is the source of truth for Steps 2-4. Never derive later scope from discovery-only inputs.DIMENSIONAL_SCOPE.json.in_scope_files- When a later step reaches terminal
, persist the matchingBLOCKED
andstep*_reason
fields on the file entry instep*_retry_count
.DIMENSIONAL_SCOPE.json
must be derived from terminalcoverage.unprocessed_files
entries inBLOCKED
usingDIMENSIONAL_SCOPE.json
.{ "path": "...", "blocked_step": "step2|step3|step4", "reason": "...", "retry_count": 1 }- A step may retry a
file once with a focused prompt. If it is stillBLOCKED
, keep the documented reason and continue. Do not finalize while any file remainsBLOCKED
.PENDING
Step 1: Vocabulary and Scope Discovery
If cached artifacts cannot be reused, delegate repository scanning to
arithmetic-scanner and vocabulary discovery to dimension-discoverer. Do not do that step-specific analysis directly in the main skill context.
- Check whether
andDIMENSIONAL_UNITS.md
already exist in the project root.DIMENSIONAL_SCOPE.json - If both exist, read them and confirm:
matches the current repo rootDIMENSIONAL_SCOPE.json.project_root
containsDIMENSIONAL_SCOPE.json
,in_scope_files
,discoverer_focus_files
, and per-filerecommended_discovery_order
,step2
,step3
fieldsstep4
is a usable dimensional vocabulary for this repoDIMENSIONAL_UNITS.md
- If either artifact is stale, malformed, missing required structure, or clearly for another repo, discard reuse and rerun the rest of Step 1.
- If both artifacts are valid, reuse them directly. If
is empty, skip Steps 2-4 and produce final output with zero findings.in_scope_files - Otherwise use the
tool to spawn theTask
agent. Its prompt must include:arithmetic-scanner- project root path
- absolute output path for
DIMENSIONAL_SCOPE.json - instruction to write the Step 1 scope manifest to disk and return the same scope data in its report
- The scanner owns Step 1 scope persistence. It must:
- identify dimensional-arithmetic files and prioritize them as usual
- write
withDIMENSIONAL_SCOPE.json
,project_root
,in_scope_files
, anddiscoverer_focus_filesrecommended_discovery_order - initialize every in-scope file with
,step2: "PENDING"
, andstep3: "PENDING"step4: "PENDING" - still write an empty manifest when no arithmetic files are found
- still narrow
to CRITICAL/HIGH when more than 50 arithmetic files are found, while keeping all priorities indiscoverer_focus_filesin_scope_files
- After the scanner completes, read
from disk and confirm it exists and contains the required Step 1 fields before continuing.DIMENSIONAL_SCOPE.json - Use the
tool to spawn theTask
agent. Its prompt must include:dimension-discoverer- project root path
- absolute path to
DIMENSIONAL_SCOPE.json - absolute output path for
DIMENSIONAL_UNITS.md - prioritized
with each file's path, priority, score, and categorydiscoverer_focus_files recommended_discovery_order
- The discoverer owns Step 1 vocabulary persistence. It must read
as the Step 1 source of truth and writeDIMENSIONAL_SCOPE.json
withDIMENSIONAL_UNITS.md
,Base Units
, andDerived Units
sections. IfPrecision Prefixes
is empty, it must still write the same headings with empty sections.in_scope_files - Step 1 is complete only when both artifacts exist on disk, pass the reuse checks above, and correctly represent the zero-file case. If
is empty after the discoverer writesin_scope_files
, skip Steps 2-4 and produce final output with zero findings.DIMENSIONAL_UNITS.md
Step 2: Anchor Annotation
The main skill context must not add annotations itself. Use the
Task tool to spawn dimension-annotator agents for all anchor-point annotation work. For full examples and annotation format details, see [{baseDir}/references/annotate.md]({baseDir}/references/annotate.md).
- Read
and build batches fromDIMENSIONAL_SCOPE.json
. Every in-scope file, including MEDIUM and LOW priority files, must receive a Step 2 outcome.in_scope_files - Batch files instead of spawning one agent per file:
files: one batch<= 10
files: one batch per category11-30
files: one batch per category, splitting categories larger than 10 files into sub-batches of about 8 files> 30
- Launch categories in Step 1 recommended discovery order: math libraries, then oracles, then core logic, then peripheral. Batches inside the same category may run in parallel.
- Before launching annotators, set
for every in-scope file and persist the updatedstep2 = "PENDING"
.DIMENSIONAL_SCOPE.json - Each annotator prompt must include:
- absolute path to
DIMENSIONAL_UNITS.md - absolute path to
DIMENSIONAL_SCOPE.json - assigned file paths in order
- each file's category and matched patterns from scanner output
- summary of previously annotated interfaces or types from earlier batches, when applicable
- required per-file status output:
,ANNOTATED
, orREVIEWED_NO_ANCHOR_CHANGES
plus a one-line justificationBLOCKED
- absolute path to
- After each batch, immediately persist each assigned file to exactly one Step 2 status:
ANNOTATEDREVIEWED_NO_ANCHOR_CHANGESBLOCKED
- If a file is
, also persistBLOCKED
andstep2_reason
. Retry eachstep2_retry_count
file once with a focused prompt.BLOCKED - Do not continue to Step 3 while any file remains
in on-disk manifest state.PENDING
Step 3: Dimension Propagation
The main skill context must not perform propagation reasoning itself. Use the
Task tool to spawn dimension-propagator agents to extend annotations through arithmetic, function calls, and assignments. For algebra details, see [{baseDir}/references/dimension-algebra.md]({baseDir}/references/dimension-algebra.md).
- Read
and build propagation batches fromDIMENSIONAL_SCOPE.json
. Every in-scope file must receive a Step 3 outcome.in_scope_files - Use the same batching rules and category ordering as Step 2.
- Before launching propagators, confirm every file already has a non-pending Step 2 status.
- Then set
for every in-scope file and persist the updated manifest.step3 = "PENDING" - Each propagator prompt must include:
- absolute path to
DIMENSIONAL_UNITS.md - absolute path to
DIMENSIONAL_SCOPE.json - assigned file paths in order
- each file's category and matched patterns
- summary of Step 2 anchor annotations for the assigned files and any upstream interfaces they depend on
- required per-file status output:
,PROPAGATED
, orREVIEWED_NO_PROPAGATION_CHANGES
plus a one-line justificationBLOCKED
- absolute path to
- After each batch, immediately persist each assigned file to exactly one Step 3 status:
PROPAGATEDREVIEWED_NO_PROPAGATION_CHANGESBLOCKED
- If a file is
, also persistBLOCKED
andstep3_reason
. Retry eachstep3_retry_count
file once with a focused prompt.BLOCKED - After all propagators complete, aggregate:
- annotations added by confidence level (
,CERTAIN
,INFERRED
)UNCERTAIN - mismatches found, with severities for validator deduplication
- coverage gaps that could not be inferred
- annotations added by confidence level (
- Do not continue to Step 4 while any file remains
in on-disk manifest state.PENDING
Step 4: Bug Detection
The main skill context must not perform bug detection itself. Use the
Task tool to spawn dimension-validator agents to detect dimensional bugs in annotated code. For examples, red flags, rationalization checks, and standard vocabulary, see [{baseDir}/references/bug-patterns.md]({baseDir}/references/bug-patterns.md), [{baseDir}/references/common-dimensions.md]({baseDir}/references/common-dimensions.md), and [{baseDir}/references/dimension-algebra.md]({baseDir}/references/dimension-algebra.md). DO NOT DETECT BUGS IN ANY OTHER STEP.
- Validate every file in
.DIMENSIONAL_SCOPE.json.in_scope_files - Use this priority order without skipping lower tiers:
- files with CRITICAL or HIGH Step 3 mismatches
- remaining CRITICAL and HIGH scanner-priority files
- remaining MEDIUM and LOW files
- Before launching validators, confirm every file already has a non-pending Step 3 status.
- Then set
for every in-scope file and persist the updated manifest.step4 = "PENDING" - Spawn one
agent per file. For large repos, run them in waves of roughly 10-30 files to keep orchestration stable.dimension-validator - Each validator prompt must include:
- absolute path to
DIMENSIONAL_UNITS.md - absolute path to
DIMENSIONAL_SCOPE.json - the single file path to validate
- a summary of anchor and propagated annotations in the file
- Step 3 mismatch summaries for the file, including mismatch IDs
- cross-file function signatures or return dimensions needed for call-boundary checks
- required per-file status output:
orVALIDATEDBLOCKED
- absolute path to
- After each wave, immediately persist each file to exactly one Step 4 status:
VALIDATEDBLOCKED
- If a file is
, also persistBLOCKED
andstep4_reason
. Retry eachstep4_retry_count
file once with a focused prompt.BLOCKED - Deduplicate findings:
- confirmed Step 3 mismatches keep their original IDs and severities
- refuted Step 3 mismatches are noted as false positives and excluded from final counts
- genuinely new findings receive new
IDsDIM-XXX
- Aggregate confirmed findings, new findings, refuted findings, coverage summary, and final
.coverage.unprocessed_files - Step 4 is complete only when
contains noDIMENSIONAL_SCOPE.json.in_scope_files
entries.step4: "PENDING"
Reference Documentation
Pass these references to the relevant subagent when a step needs them:
- Propagator and validator algebra rules[{baseDir}/references/dimension-algebra.md]({baseDir}/references/dimension-algebra.md)
- Validator vocabulary reference[{baseDir}/references/common-dimensions.md]({baseDir}/references/common-dimensions.md)
- Validator bug-pattern and red-flag reference[{baseDir}/references/bug-patterns.md]({baseDir}/references/bug-patterns.md)
- Annotator format and example reference[{baseDir}/references/annotate.md]({baseDir}/references/annotate.md)
Final Output
At the end of the analysis, provide a structured summary unless some other output format has been specified:
{ "mode": "full-auto", "project_root": "<path>", "vocabulary": { "base_units": ["..."], "derived_units": ["..."], "precision_prefixes": ["..."] }, "annotations": { "total_added": 0, "by_file": {} }, "findings": { "critical": 0, "high": 0, "medium": 0, "details": [] }, "uncertainties_resolved": 0, "coverage": { "in_scope_files": 0, "anchor_reviewed_files": "0/0", "propagation_reviewed_files": "0/0", "validation_reviewed_files": "0/0", "annotated_functions": "0/0", "annotated_variables": "0/0", "unprocessed_files": [ { "path": "/path/to/repo/contracts/LegacyMath.sol", "blocked_step": "step3", "reason": "Parser could not process generated source", "retry_count": 1 } ] } }
Completion Checklist
You are NOT done until all of these are true:
File Coverage Gates
-
exists in the project rootDIMENSIONAL_UNITS.md -
exists in the project root and is the source of truth for downstream coverageDIMENSIONAL_SCOPE.json - Every in-scope arithmetic file discovered in Step 1 appears in
DIMENSIONAL_SCOPE.json.in_scope_files - Every in-scope file has a non-
Step 2 status (PENDING
,ANNOTATED
, orREVIEWED_NO_ANCHOR_CHANGES
)BLOCKED - Every in-scope file has a non-
Step 3 status (PENDING
,PROPAGATED
, orREVIEWED_NO_PROPAGATION_CHANGES
)BLOCKED - Every in-scope file has a non-
Step 4 status (PENDING
orVALIDATED
)BLOCKED - No in-scope file remains
in any stepPENDING - Any
file has a documented reason in the final outputBLOCKED -
exactly matches the final set of terminalcoverage.unprocessed_files
files after retries, usingBLOCKED
,path
,blocked_step
, andreasonretry_count
Summary Report
- Final summary JSON/report provided
- Final coverage counters match
DIMENSIONAL_SCOPE.json - List of modified files provided when edits occurred
- Any dimensional mismatches or bugs found are summarized
- Any remaining blocked or unprocessed files are called out with reasons
If
and the final report disagree, reconcile the report or continue processing until they match.
Do not claim completion from agent intent alone; completion is determined by manifest coverage and final reported statuses.DIMENSIONAL_SCOPE.json