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slack-block-kit

Build Slack Block Kit UIs for messages, modals, and Home tabs. Use when creating Slack notifications, interactive forms, bot responses, app dashboards, or any Slack UI. Covers blocks (Section, Actions, Input, Header), elements (Buttons, Selects, Date pickers), composition objects, and the slack-block-builder library.

67

Quality

84%

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SKILL.md
Quality
Evals
Security

Quality

Content

65%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.

A highly actionable, well-organized reference with excellent copy-paste JSON and slack-block-builder examples, but it behaves as a monolithic API catalog: the detailed block/element documentation inlined here duplicates what the (missing) references/ files are supposed to hold, and there is no explicit build-then-validate workflow. Verdict: strong examples, weak file structure.

Suggestions

Move the Blocks Reference, Elements Reference, Composition Objects, and Modal Reference sections into the references/ files the Resources section already points to, keeping only the Quick Start, a few key examples, and the pointers in SKILL.md — and make the link paths bundle-relative (references/blocks.md, not ../../references/blocks.md) so they resolve.

Add a short numbered workflow (assemble payload → validate in Block Kit Builder or via API response → fix and re-validate) so the existing Troubleshooting table becomes an explicit feedback loop.

Trim the Overview's explanation of what Block Kit is and drop redundant per-element examples that repeat patterns already shown in Quick Start and Common Patterns.

DimensionReasoningScore

Conciseness

The body is dense with genuinely non-obvious specifics (char limits, block/element compatibility, surface limits), but the ~1200-line catalog includes unnecessary explanation of concepts Claude already knows ("Block Kit is Slack's UI framework... three main components") and duplication: a full JSON example plus field list for every element, while a Resources section simultaneously points to references/ files described as "Detailed documentation on all block types" covering the same ground. This sits between anchor 2 ('several unnecessary explanations or padded sections') and anchor 3 ('mostly efficient but some unnecessary explanation'); the useful reference data keeps it at 3 rather than 2.

3 / 5

Actionability

Everything is copy-paste ready: complete valid JSON payloads for each block/element, executable slack-block-builder JavaScript ("Message({ channel, text: 'New Order Received' }).blocks(...).buildToObject()"), an install command ("npm install slack-block-builder"), named common patterns, and a concrete error→cause→solution table. Not the 4 anchor because there are no pseudocode or missing-key-details gaps: examples cover the common message, modal, and Home tab cases end to end.

5 / 5

Workflow Clarity

This is a reference-catalog skill, so organization (Quick Start → Blocks → Elements → Patterns → Troubleshooting) substitutes for a step sequence, and validation appears only as a tip ("Use Block Kit Builder to test JSON") in a numbered tip list rather than as an explicit checkpoint in a build-validate workflow. That matches anchor 3 ('sequence present but checkpoints missing or implicit'); it is not 4 because no explicit sequenced workflow with validation steps is ever laid out, and not 2 because navigation between sections is coherent with a concrete troubleshooting table.

3 / 5

Progressive Disclosure

Structure and signaling are good (clear headers, a dedicated Resources section with bolded links to references/blocks.md, interactive-components.md, layout-patterns.md, surfaces.md), but the bulk of the API reference that belongs in those files is inlined in SKILL.md, and the referenced files do not exist in this bundle (the links use ../../references/ paths and no references/ directory is present). This fits anchor 3 ('references present but content that should be separate is inline'); not 4 because the split is only nominal — the inline catalog defeats the disclosure — and not 2 because sections are well organized and the references are clearly signaled rather than buried.

3 / 5

Total

14

/

20

Passed

Description

100%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.

The description is a model example: it states what the skill does concretely, gives an explicit and natural 'Use when' trigger list, and occupies a distinct niche in third-person voice. No changes needed.

DimensionReasoningScore

Specificity

"Build Slack Block Kit UIs for messages, modals, and Home tabs" plus "Covers blocks (Section, Actions, Input, Header), elements (Buttons, Selects, Date pickers), composition objects, and the slack-block-builder library" enumerates multiple concrete capabilities and their scope. Coverage is comprehensive for the domain and written in third person, matching the top anchor rather than the 'several specific actions; minor gaps' of 4.

5 / 5

Completeness

The "what" is explicit ("Build Slack Block Kit UIs for messages, modals, and Home tabs... Covers blocks... elements... composition objects") and the "when" is explicit with concrete triggers ("Use when creating Slack notifications, interactive forms, bot responses, app dashboards, or any Slack UI"). This directly matches the anchor-5 exemplar structure.

5 / 5

Trigger Term Quality

"Use when creating Slack notifications, interactive forms, bot responses, app dashboards, or any Slack UI" captures the natural phrases a user would say, alongside the technical terms (Block Kit, messages, modals, Home tabs, slack-block-builder). The trailing "or any Slack UI" broadens coverage so no common variation is meaningfully missed; the 4 anchor ('a few natural terms missing') would understate it.

5 / 5

Distinctiveness Conflict Risk

The niche is narrow (Slack's Block Kit UI framework) with distinctive triggers (notifications, modals, Home tabs, block-kit builder). Only a hypothetical generic 'Slack API' skill could overlap, which is the minimal-conflict profile of the top anchor; the 4 anchor's 'minor overlap risk with closely related skills' does not fit better.

5 / 5

Total

20

/

20

Passed

Validation

81%

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

Validation — 13 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

skill_md_line_count

SKILL.md is long (1207 lines); consider splitting into references/ and linking

Warning

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

relative_links

Relative link issues: 4 suspicious

Warning

Total

13

/

16

Passed

Repository
freightCognition/linehaulai-claude-marketplace
Reviewed

Table of Contents

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