Conciseness

The body is lean throughout — checklist-style inputs, direct command blocks, and terse decision points with no re-teaching of concepts Claude already knows (no "what ChIP-seq is" filler). Not 4 because there is no identifiable padding to trim; every section carries actionable content.

Actionability

Commands are fully executable and copy-paste ready with real flags, paths, and named outputs ("--peak-mode narrow", "--bowtie2-index /refs/GRCh38/bowtie2/genome", emitted "qc/chip_cutrun_qc_summary.{tsv,json}"), and the examples cover the common cases (chipseq/tf/narrow plus nf-core routes). Not 4 because the command blocks are complete rather than having minor gaps.

Workflow Clarity

A clear sequence is present — confirm inputs, run preflight, route (nf-core vs direct MACS2 vs dedicated runner), then check QC metrics ("alignment rate, duplicate rate, fragment size, FRiP/peak signal, blacklist overlap, and replicate concordance") — and validation exists (preflight, resource readiness gating), so the batch-operation cap does not apply. Not 5 because there are no explicit error-recovery feedback loops (e.g., what to do when FRiP or replicate concordance fails); not 3 because validation checkpoints are explicitly present, not merely implied.

Progressive Disclosure

The single SKILL.md is well-organized into Essential Inputs, Route, Decision Points, and Outputs with no nested references and no content that plainly belongs in a separate file. Not 5 because there are no well-signaled one-level-deep references for deeper material (a runner flag reference or sample-sheet schema would fit naturally in a references/ file); not 3 because structure is clean and nothing bulky is mis-inlined.

Specificity

The description enumerates multiple concrete actions — "QC, control handling, spike-in, peak calling, broad-vs-narrow target selection, replicate, bigWig, and differential binding" — giving comprehensive coverage of the skill's workflow surface. Not level 4 because no meaningful capability is left out; the action list is specific rather than having minor gaps.

Completeness

The "what" is clear ("Run or plan ... QC ... peak calling ... differential binding workflows"), but there is no "Use when..." clause or equivalent explicit trigger guidance, which caps this dimension at 3 per the judging guidelines. Not 4 because the "when" is entirely absent rather than merely under-specified.

Trigger Term Quality

Strong natural keywords users would actually say: "ChIP-seq", "CUT&RUN", "CUT&Tag", "peak calling", "QC", "bigWig", "differential binding". Not 5 because common variations and file extensions are absent (e.g., ".fastq", ".bam", "antibody", "histone mark"), leaving a few natural entry points uncovered; not 3 because synonym coverage across the three assay names is present and well-matched.

Distinctiveness Conflict Risk

Names a clear niche via the three specific antibody-targeted enrichment assays, with trigger vocabulary (peak calling, bigWig, differential binding) that is distinct from the sibling ATAC-seq skill. Not 4 because the assay terms themselves disambiguate it from closely related genomics skills with minimal overlap risk.