Conciseness

The body is dense and imperative — phases, tables, and bullet directives with almost no explanation of concepts Claude already knows (e.g., the DB section jumps straight to "CREATE INDEX CONCURRENTLY, pg_repack, gh-ost, start batch=1000"). Minor trimmable redundancy exists: the persona paragraph ("You are a senior staff engineer... You've seen spikes that changed architectural direction") and the duplicated instruction "Every section must be populated" in 3.2.

Actionability

Concrete guidance is substantial (parallel subagent assignments, category classification rules, explicit save paths, a 10-row quality gates table, specific DB techniques), but key details are missing: "Follow the template in `spike-template.md`" and "Read `company-config.yaml` from the skill directory" point to files that do not exist in the bundle, and external skills ("Invoke grill-me", "devflow:codebase-walkthrough", "devflow:retain-learning", Nimbalist task files) are invoked with no bundled definitions or inline fallbacks, so the document-generation phase is not executable as shipped.

Workflow Clarity

The four phases are explicitly sequenced (reinforced by a Mermaid flowchart and "Every phase is mandatory. Do not skip phases."), with validation checkpoints throughout: a scope check after Phase 1 with concrete thresholds ("30+ spike goals, 10+ external dependencies"), user decision points ("Decide now, discuss with team, or defer?"), a 10-gate quality checklist in 3.4, and a self-review feedback loop in 4.1 ("Placeholder scan, internal consistency, scope check, ambiguity check. Fix inline.") plus grill-me adversarial review in 4.2. Defaults and safety rails are explicit ("Default: keep local. Never auto-publish.").

Progressive Disclosure

Section structure per phase is good and references are clearly signaled one level deep ("REQUIRED REFERENCE: Follow the template in `spike-template.md` (same directory as this skill)"), but no bundle directory exists and neither referenced file (spike-template.md, company-config.yaml) is present, so the navigation chain is broken and the skill functions as a monolith with dangling references. This is between anchor 3 (references present but the organization is incomplete) and anchor 2, landing at 3 because the in-body structure itself is well organized.

Specificity

Concrete deliverables are named — "produces a structured spike doc with diagrams and a private notes file" — alongside specific activities like "investigating technical feasibility" and "assessing impact across services". It falls short of anchor 5 because it does not enumerate multiple specific actions of the process itself (the anchors' comprehensiveness), but is clearly above anchor 3's '1-2 concrete actions'.

Completeness

Both questions are answered explicitly and with concrete trigger phrases: an explicit "Use when starting a new initiative spike, investigating technical feasibility, ..." clause for 'when', and "produces a structured spike doc with diagrams and a private notes file" for 'what'. The 'when' is highly explicit with four distinct conditions, matching anchor 5 rather than anchor 4 ('when could be more explicit').

Trigger Term Quality

Natural trigger phrases a user would say include "initiative spike", "technical feasibility", "engineering discovery document", and "assessing impact across services". Common synonyms such as 'POC', 'proof of concept', or 'spike document' as a standalone noun are only partially covered, matching anchor 4's 'good keyword coverage; a few natural terms missing'.

Distinctiveness Conflict Risk

The niche is distinct — 'spike' / 'engineering discovery document' with a specific two-file deliverable — making wrong-skill triggering unlikely. It is not anchor 5 because broader phrases like "investigating technical feasibility" and "assessing impact across services" could overlap with general research/architecture-review skills.