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gcp-spark

Develops and executes Spark code on Dataproc Clusters and Serverless. Reads and writes data using BigLake Iceberg catalogs, BigQuery and Spanner. Debugs execution failures. Use when: - Writing Spark ETL pipelines on GCP. - Training or running inference with ML models with spark on GCP. - Managing Spark clusters, jobs, batches, and interactive sessions. Don't use when: - Writing generic Python scripts that don't use Spark. - Performing simple SQL queries that can be done directly in BigQuery.

Quality

83%

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SKILL.md
Quality
Evals
Security

Quality

Content

71%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The body is an efficient, actionable workflow with real validation checkpoints and a high-value mistakes checklist. Its main weaknesses are the absence of an explicit error-recovery loop and the fact that all detailed guidance lives in resource files that are not present in the bundle, leaving the skill's own references unresolvable.

Suggestions

Ship the referenced files with the bundle (resources/read_write_data.md, resources/spark_optimizations.md, resources/gcloud_dataproc.md, resources/schema_direct_inspection.md, resources/ml_tasks.md) or inline the essential read/write and optimization guidance, since none of the referenced paths currently resolve.

Add an explicit feedback loop after the verify/compile steps, e.g. "If the schema mismatches or compilation fails: fix the code and re-run verification before executing" — batch Spark jobs are exactly the context where validate-fix-retry loops matter.

Deduplicate the schema-inspection reference (repeated in workflow steps 1 and 3) and the gcloud_dataproc.md reference (repeated in step 5 and the resource-management section) to trim tokens without losing information.

DimensionReasoningScore

Conciseness

The body is lean and imperative with no explanation of concepts Claude already knows — the checklist items capture genuinely non-obvious knowledge ("`vector_to_array` from correct module", "Avoid toPandas()"). Minor tightening is possible: the schema-inspection reference is repeated in steps 1 and 3, `resources/gcloud_dataproc.md` is referenced twice, and the horizontal rules add no information, so it fits the 4 anchor rather than the every-token-earns-its-place 5.

4 / 5

Actionability

Mostly executable guidance: copy-paste-ready commands ("jupyter nbconvert --to script your-notebook.ipynb", "python3 -m py_compile your-notebook.py"), a precise import correction ("from pyspark.ml.functions import vector_to_array"), and a concrete IAM role list. It falls short of 5 because the core task — reading/writing data — has no inline code example and defers entirely to `resources/read_write_data.md`.

4 / 5

Workflow Clarity

A clear 5-step sequence with two explicit pre-execution validation checkpoints ("Verify schema before write" via `df.printSchema()`, "Compile code before executing") plus a caution checklist for batch job submission. It does not reach 5 because there is no error-recovery feedback loop — nothing instructs what to do when the schema check fails or compilation errors appear.

4 / 5

Progressive Disclosure

Sections are well organized and every reference is clearly signaled with its purpose (e.g., "ALWAYS Refer to `resources/read_write_data.md` when reading or writing data"), but none of the referenced `resources/*.md` files exist in the bundle — there are no references/, scripts/, or assets/ directories — so navigation to the deferred detail content fails and the paths used ("resources/") don't match standard bundle locations. The in-file structure is good but the external structure is broken, matching the 3 anchor's "could be better organized" better than the 2 anchor's "references buried".

3 / 5

Total

15

/

20

Passed

Description

87%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description in consistent third-person voice: concrete capabilities tied to named GCP technologies, explicit use/don't-use triggers, and low conflict risk. The only gap is trigger-term breadth (missing synonyms like PySpark) and slightly coarse action granularity.

DimensionReasoningScore

Specificity

Lists several concrete actions naming specific technologies — "Develops and executes Spark code on Dataproc Clusters and Serverless", "Reads and writes data using BigLake Iceberg catalogs, BigQuery and Spanner", "Debugs execution failures" — but the actions stay coarse-grained rather than the fine-grained, comprehensive enumeration of the 5 anchor.

4 / 5

Completeness

Explicitly answers both questions: the "what" via three capability sentences, and the "when" via a literal "Use when:" list with three concrete triggers — plus "Don't use when" exclusions, which exceeds the 5 anchor's requirement for concrete trigger phrases.

5 / 5

Trigger Term Quality

Natural user phrases like "Writing Spark ETL pipelines on GCP" and "Managing Spark clusters, jobs, batches, and interactive sessions" give good coverage, but common synonyms users actually say — notably "PySpark" and "Dataproc serverless" phrasings — are missing, keeping it below the 5 anchor without dropping to the patchy coverage of a 3.

4 / 5

Distinctiveness Conflict Risk

A clear niche (Spark on GCP/Dataproc with named GCP data systems) with distinct triggers, and the negative trigger "Performing simple SQL queries that can be done directly in BigQuery" explicitly disambiguates from adjacent BigQuery and generic-Python skills, giving minimal conflict risk.

5 / 5

Total

18

/

20

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository

saski/arnesto

Path

.agents/skills/gcp-spark/SKILL.md

Reviewed

Table of Contents

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