Conciseness

The body is mostly efficient and contains no boilerplate explanations of concepts Claude already knows, but the ~450-word styling-depth paragraph ("A reference design is a checklist of regions (header, composer buttons, where the timestamp + read receipts sit...)" plus the four numbered traps) and the workplace/Liquid Glass paragraph inline runbook-level detail that duplicates the referenced design-matching.md and custom-ui.md. Not 2: everything inlined is curated non-obvious knowledge, not padding; not 4: several mega-paragraphs restate content already delegated to referenced files and could be tightened to routing rules.

Actionability

Fully executable instruction-only guidance: the exact URL convention with a concrete example ("take the page URL, drop the trailing /, add .md"), a live index table with exact URLs, "Fetch at most 3 pages per request", a verbatim citation format ("Source: [Title](https://getstream.io/...)") and "Never answer SDK specifics from training data", named escalation files ("read ViewFactory.swift (every slot) + DefaultViewFactory.swift"), and even verbatim clarifying questions. Not 4: even the ambiguity-handling paths are copy-paste ready.

Workflow Clarity

Clear ordered sequence: "Step 0: Classify the request (always first)" -> Setup for integrate/new app -> "Step 1: Docs lookup (every request ends here)" with numbered application steps, plus an explicit iterate loop for design work ("The match is not done until you build, run, seed data that triggers every region, compare region-by-region ... and iterate"). Not 5: validation/feedback checkpoints are only spelled out for the design-matching path — the plain docs-lookup and integrate flows have grounding rules but no verify step; not 3: the sequence is explicit and well-dispatched by mode.

Progressive Disclosure

One-level-deep references, each well signaled with its purpose: "RULES.md - non-negotiable rules + iOS pitfalls. Read before writing any code", the setup.md numbered flow, and a closing "What this skill no longer carries" section that enumerates every runbook. Not 5: heavy runbook detail is inlined in SKILL.md instead of living solely in the referenced files, two references point outside the skill directory ("../stream/sendbird-data-migration.md", "../stream/ai-backend-contract.md"), and none of the referenced files (RULES.md, docs-map.md, setup.md, push.md, ai-integration.md, design-matching.md, custom-ui.md, sendbird-migration.md) are present in this skill bundle to verify they resolve. Not 3: references are clearly signaled, single-level, and purpose-stated.

Specificity

Lists multiple concrete actions with comprehensive coverage: "Build, integrate, migrate to, and answer how-to questions for Stream Chat, Video, and Feeds in Swift / SwiftUI / UIKit / iOS apps", "Routes each request to the exact official iOS docs page, fetches it live, and applies it", plus named deliverables ("a curated setup flow, an AI integration runbook, a Sendbird -> Stream Chat migration runbook"). Uses third person ("Routes", "fetches", "applies") so no voice penalty applies. Not 4: coverage spans all three products, both UI frameworks, and four distinct modes with named runbooks — comprehensive rather than minor gaps.

Completeness

The 'what' is explicit (build/integrate/migrate/how-to plus docs routing), and the 'when' is carried by the enumerated request types ("Build, integrate, migrate to, and answer how-to questions for Stream Chat, Video, and Feeds in ... iOS apps") — equivalent trigger guidance, so the missing-Use-when cap at 3 does not apply. Not 5: there is no explicit "Use when..." clause, so the 'when' could be more direct; not 3: the enumerated request types are explicit trigger guidance, not weakly implied.

Trigger Term Quality

Natural user phrasings are comprehensively covered with synonyms: "Stream Chat, Video, and Feeds", "Swift / SwiftUI / UIKit / iOS apps", "ChatGPT-style apps, LLM bots in chat, streaming responses, thinking indicators, client-side MCP tools", "Sendbird -> Stream Chat". A user asking to "migrate from Sendbird" or "build a ChatGPT-style app in SwiftUI" would naturally say these terms. Not 4: it covers both product names and colloquial synonyms for the AI-agent space; file extensions are not applicable to this domain.

Distinctiveness Conflict Risk

Clear niche with distinct triggers: "Stream Chat, Video, and Feeds", "StreamChatAI components", and "Sendbird -> Stream Chat migration runbook" are unique anchors that no generic Swift/iOS or docs skill would claim. Not 4: the Sendbird-migration and StreamChatAI phrasing makes overlap with a sibling general Swift skill essentially nil.