NIP-CRAFTS: Craft Technique Documentation

Published Mar 27, 2026

kind 30401

NIP-CRAFTS

Craft Technique Documentation

draft optional

One addressable event kind for craft technique documentation on Nostr. Practitioner skill identity composes with NIP-PROVIDER-PROFILES.

Standalone. This NIP works independently on any Nostr application. Composition with NIP-PROVIDER-PROFILES, NIP-MENTORSHIP, NIP-SCARCITY, and NIP-REPUTATION is OPTIONAL.

Motivation

Nostr has no standard for structured craft technique documentation. A heritage craft technique practised by three remaining practitioners has no structured format for preservation. Practitioner skill identity is handled by [NIP-PROVIDER-PROFILES](./NIP-PROVIDER-PROFILES.md) (kind 30510), which already supports skill, credential, and domain tags. This NIP extends that foundation with craft-specific tags and adds a dedicated Technique Record kind for living documentation.

Current approaches lack:

Technique preservation - no standard for documenting craft processes with sufficient structure for discovery, versioning, and licensing
Structured skill declaration - no way to express proficiency levels, specialisms, traditions, or endangerment status in a discoverable, filterable format (addressed here via craft:* extension tags on Provider Profiles)
Cross-reference to credentials - no link between self-declared skills and third-party attestations
Endangerment awareness - no way to flag skills or techniques at risk of being lost

Cross-Domain Evidence

This NIP was promoted from incubating after demonstrating demand across 4+ unrelated domains:

Domain	Use case	Category
Heritage conservation	Heritage crafts taxonomy - 17 categories, 100+ specialisms, proficiency levels, prerequisite chains for 165 endangered crafts	Built environment
Craft/making (therapeutic)	Craft skill identity and technique documentation for pottery, weaving, metalwork, woodcraft	Creative arts
Outdoor education	Skill progressions across 20+ National Governing Bodies (Forest School, Mountain Training, RYA, BCU)	Education
Veteran support	Military-to-civilian skills translation - mapping military qualifications and experience to civilian job descriptions	Social services
Japanese woodworking	Traditional joinery techniques (kumiki, tsugite), temple carpentry traditions, Living National Treasure preservation	Built environment
Italian marble sculpting	Carrara marble sculpting traditions, apprenticeship lineages, tool technique documentation	Creative arts
Nordic boat-building	Clinker-built boat traditions (Viking-era revival), Scandinavian maritime craft preservation	Maritime

These domains span built environment, creative arts, education, social services, and maritime, confirming the pattern is domain-agnostic.

Kinds

Kind	Description
30401	Technique Record

Composing with NIP-PROVIDER-PROFILES

A practitioner's skill identity is expressed as a [NIP-PROVIDER-PROFILES](./NIP-PROVIDER-PROFILES.md) kind:30510 event with craft:* extension tags. This avoids a dedicated Skill Profile kind; a Provider Profile is the natural home for "who I am and what I can do." Even a retired master who is not available for hire can use a Provider Profile with no standing_offer or availability tags.

Clients that understand crafts read the craft:* tags for proficiency levels, tradition, endangerment status, and specialism. Generic clients see a standard provider profile with domain, skill, and credential tags.

Example: Blacksmith Skill Profile

{
    "kind": 30510,
    "tags": [
        ["d", "<pubkey>_profile"],
        ["alt", "Craft practitioner profile: master blacksmith, architectural ironwork"],
        ["t", "domain:metalwork"],
        ["t", "skill:forge_work"],
        ["t", "skill:wrought_iron"],
        ["t", "credential:worshipful_company_blacksmiths:fellow"],
        ["domain", "metalwork"],
        ["skill", "forge_work"],
        ["skill", "wrought_iron"],
        ["craft:proficiency", "master"],
        ["craft:specialism", "architectural_ironwork"],
        ["craft:years_practising", "28"],
        ["craft:tradition", "english_ornamental_ironwork"],
        ["craft:endangerment", "hca:endangered"],
        ["craft:available_for", "commission"],
        ["craft:available_for", "teaching"],
        ["craft:location", "gcpvhd"],
        ["craft:certification", "worshipful_company_blacksmiths:fellow"],
        ["craft:certification", "hetas:registered_installer"]
    ],
    "content": "Master blacksmith specialising in architectural ironwork..."
}

The craft:* tags are the extension layer on top of NIP-PROVIDER-PROFILES. The domain, skill, and credential tags (plus their t-tag equivalents for relay indexing) follow the standard Provider Profile conventions. The craft:* tags add craft-specific semantics that generic clients can safely ignore.

Craft-Specific Tag Vocabulary

Extensibility: The craft:* tag namespace is open. Applications MAY define additional tags following the craft:<attribute> convention. The tags listed here are RECOMMENDED for interoperability.

These tags extend a kind:30510 Provider Profile for craft practitioners:

craft:proficiency (OPTIONAL): Self-assessed proficiency level. One of awareness, developing, competent, experienced, master.
craft:specialism (OPTIONAL, repeatable): Narrow specialism within a skill (e.g. hot_lime_plastering within lime_work, architectural_ironwork within forge_work).
craft:years_practising (OPTIONAL): Years of active practice. Integer as string.
craft:tradition (OPTIONAL): Cultural or regional tradition (e.g. japanese_joinery, welsh_coracle, sussex_trug, english_ornamental_ironwork).
craft:endangerment (OPTIONAL): Endangerment status in registry:status format (e.g. hca:critically_endangered, unesco:urgent_safeguarding). See the endangerment registries table below.
craft:available_for (OPTIONAL, repeatable): What the practitioner offers. Values: teaching, commission, demonstration, documentation, assessment.
craft:workshop (OPTIONAL): Whether the practitioner has a workshop or studio visitors can attend. Boolean as string ("true" or "false").
craft:certification (OPTIONAL, repeatable): Certification reference in body:identifier format (e.g. spab:fellow, gas_safe:123456, cscs:gold). Works with any certification system worldwide.
craft:mentorship_ref (OPTIONAL, repeatable): Event reference to a [NIP-MENTORSHIP](./NIP-MENTORSHIP.md) endorsement (Kind 30517 with endorsement_type: "mentorship"). Links the practitioner's training lineage to their profile.
craft:certification_ref (OPTIONAL, repeatable): Event reference to a [NIP-REPUTATION](./NIP-REPUTATION.md) Credential Attestation (NIP-VA kind 31000). Links third-party credential verification to the profile.
craft:scarcity_signal (OPTIONAL, repeatable): Event reference to a [NIP-SCARCITY](./NIP-SCARCITY.md) signal (Kind 30599). Links the practitioner's skills to active endangerment signals.
craft:location (OPTIONAL): Practitioner's base location as a geohash. Complements the Provider Profile's coverage_geohash tags with a single primary location.

Proficiency Levels

Level	Meaning
`awareness`	Understands the craft conceptually. Has observed or studied but not practised independently.
`developing`	Learning the craft. Can perform basic tasks under guidance.
`competent`	Competent practitioner. Can work independently on standard tasks.
`experienced`	Highly skilled. Can handle complex, non-standard work and teaches others.
`master`	Recognised authority. Defines standards, preserves traditions, certifies others.

REQ Filters

Craft practitioners are discovered using standard NIP-PROVIDER-PROFILES filters with craft-specific post-filtering:

[
    {"kinds": [30510], "#t": ["domain:metalwork"]},
    {"kinds": [30510], "#t": ["skill:forge_work"], "#g": ["gcpv"]}
]

Note: Tags prefixed with craft: are multi-letter tags. Standard relays index only single-letter tags. Discovery SHOULD use #t and #g filters as shown above. Clients post-filter by craft:* tag values (proficiency, tradition, endangerment, etc.) after fetching matching events; these are client-side filters only.

Kind 30401: Technique Record

A documented craft technique - the "living archive" primitive. Each record describes one technique in sufficient detail for another practitioner to learn or reproduce it. Content is the primary value; tags enable discovery and filtering.

{
    "kind": 30401,
    "pubkey": "<practitioner-hex-pubkey>",
    "created_at": 1709740800,
    "tags": [
        ["d", "lime-pointing-flush-finish"],
        ["alt", "Technique record: Flush Lime Pointing with NHL 3.5"],
        ["craft:category", "building_conservation"],
        ["craft:skill", "lime_work"],
        ["craft:technique_name", "Flush Lime Pointing with NHL 3.5"],
        ["craft:difficulty", "intermediate"],
        ["craft:time_estimate", "PT4H"],
        ["craft:tools_required", "pointing trowel, hawk, jointing iron, spray bottle, stiff brush, bucket"],
        ["craft:materials_required", "NHL 3.5 lime putty, sharp sand (washed), clean water"],
        ["craft:tradition", "english_conservation"],
        ["craft:safety_notes", "Lime is caustic - wear nitrile gloves and eye protection. Wash skin contact immediately with clean water. Work in ventilated conditions when mixing dry lime."],
        ["craft:seasonal_constraint", "frost_sensitive"],
        ["craft:media", "https://blossom.example.com/techniques/lime-pointing-step1.jpg"],
        ["craft:media_type", "image/jpeg"],
        ["craft:media", "https://blossom.example.com/techniques/lime-pointing-demo.mp4"],
        ["craft:media_type", "video/mp4"],
        ["craft:endangerment", "hca:at_risk"],
        ["license", "CC-BY-SA-4.0"],
        ["version", "1.2.0"],
        ["L", "craft:category"],
        ["l", "building_conservation", "craft:category"]
    ],
    "content": "## Flush Lime Pointing with NHL 3.5\n\nFlush pointing restores historic masonry joints using natural hydraulic lime, matching the original mortar profile. This technique is appropriate for most pre-1919 buildings with soft brick or stone.\n\n### Preparation\n\n1. Rake out existing joints to a minimum depth of 25mm using a plugging chisel and lump hammer. Never use angle grinders - they damage arrises and leave a smooth surface that prevents adhesion.\n2. Brush out all loose material with a stiff bristle brush.\n3. Dampen joints thoroughly with a spray bottle. The masonry should be damp but not running wet.\n\n### Mix\n\nRatio: 1 part NHL 3.5 to 2.5 parts sharp washed sand (by volume). Add water gradually until the mix holds its shape when squeezed - it should feel like damp brown sugar, not wet cement.\n\n### Application\n\n1. Load the hawk with a small amount of mix.\n2. Push the mix firmly into the joint with a pointing trowel, working from bottom to top.\n3. Compact with a jointing iron, pressing firmly to eliminate voids.\n4. Finish flush with the masonry face - do not leave proud or recessed.\n\n### Aftercare\n\nProtect from direct sun, wind, and frost for a minimum of 72 hours. Mist lightly with water twice daily in warm weather to slow carbonation. NHL 3.5 achieves initial set in 24 hours but full carbonation takes 6-12 months.\n\n### Common Errors\n\n- Using cement or NHL 5 on soft masonry - too hard, causes spalling\n- Insufficient raking depth - mortar falls out within a year\n- Applying in frost - lime will not carbonate below 5\u00b0C\n- Pointing over dry masonry - causes rapid dehydration and crumbling",
    "id": "<32-byte-hex>",
    "sig": "<64-byte-hex>"
}

Tags:

d (REQUIRED): Unique identifier for this technique record.
craft:category (REQUIRED): Craft taxonomy category.
craft:skill (REQUIRED): Specific skill this technique belongs to.
craft:technique_name (REQUIRED): Human-readable technique name.
craft:difficulty (OPTIONAL): Difficulty level. One of beginner, intermediate, advanced, master.
craft:time_estimate (OPTIONAL): Estimated time to perform the technique. ISO 8601 duration format (e.g. PT2H for 2 hours, P3D for 3 days).
craft:tools_required (OPTIONAL): Comma-separated list of tools needed.
craft:materials_required (OPTIONAL): Comma-separated list of materials needed.
craft:tradition (OPTIONAL): Cultural or regional origin of the technique.
craft:safety_notes (OPTIONAL): Safety considerations. Implementations SHOULD display these prominently.
craft:seasonal_constraint (OPTIONAL): Seasonal limitations (e.g. frost_sensitive, dry_weather_only).
craft:media (OPTIONAL, repeatable): URL to media - photo, video, or diagram. Blossom recommended, any URL accepted.
craft:media_type (OPTIONAL): MIME type for the preceding craft:media tag.
craft:prerequisite (OPTIONAL, repeatable): Event reference to another Technique Record (Kind 30401) that should be learned first.
craft:endangerment (OPTIONAL): Endangerment status of this specific technique in registry:status format.
license (OPTIONAL): Content licence. RECOMMENDED values: CC-BY-4.0, CC-BY-SA-4.0, CC-BY-NC-4.0, CC0, all-rights-reserved. Defaults to all-rights-reserved if omitted.
version (OPTIONAL): Semver version. Practitioners refine technique records over time; version tracking enables consumers to detect updates.
L (OPTIONAL): NIP-32 label namespace - craft:category.
l (OPTIONAL): NIP-32 label value under the craft:category namespace.
content (REQUIRED): Structured description of the technique. Implementations SHOULD support Markdown formatting. The content is the primary value of the record.

Restricted Techniques

Certain techniques (e.g. conservation methods that could enable theft if published openly, or safety-critical procedures requiring supervised practice) MAY be encrypted using NIP-44. The tags remain public for discovery; the content field is encrypted to authorised recipients.

REQ Filters

[
    {"kinds": [30401], "#l": ["building_conservation"]},
    {"kinds": [30401], "authors": ["<practitioner-pubkey>"]}
]

Note: Tags prefixed with craft: are multi-letter tags. Standard relays index only single-letter tags. Discovery SHOULD use #l (NIP-32 labels) and authors filters as shown above. Clients post-filter by craft:* tag values after fetching matching events; these are client-side filters only.

Craft Taxonomy

Top-level categories for craft:category. This taxonomy is extensible. Applications MAY define additional categories for their domain.

Category	Description	Example skills
`building_conservation`	Historic building trades	Stone masonry, lime work, thatching, timber framing, lead roofing, dry stone walling, cob building
`metalwork`	Metal shaping and fabrication	Forge work, farriery, casting, wrought iron, blade making, armouring, bell founding, gilding
`woodcraft`	Wood-based traditional crafts	Green woodworking, coppicing, charcoal burning, coopering, bodging, hurdle making, wheelwrighting, turning
`textile_fibre`	Textile and fibre crafts	Spinning, weaving, dyeing (natural), felting, basket weaving, rope making, sail making, lace making
`food_production`	Traditional food and drink production	Brewing, milling, cheese making, curing, smoking, beekeeping, heritage breed husbandry, baking (wood-fired)
`maritime`	Boat building and seafaring crafts	Clinker planking, caulking, spar making, rigging, net making, sail making, rope splicing
`conservation_restoration`	Conservation of objects and interiors	Stained glass, gilding, fresco, bookbinding, clock/horology, furniture restoration, organ building
`bushcraft_wilderness`	Wilderness and survival skills	Fire-making, shelter building, foraging, tracking, hide tanning, cordage, natural navigation, water purification
`medieval_historical`	Historical and recreationist crafts	Armour making, calligraphy, illumination, pottery, ceramics, leather working, parchment making
`garden_landscape`	Traditional garden and land management	Walled gardens, ha-has, period planting, topiary, hedgelaying, coppice management
`clinical`	Medical and healthcare skills	Medical procedures, surgical techniques, diagnostic methods, nursing specialisms
`engineering`	Regulated engineering trades	Gas fitting, electrical installation, plumbing, HVAC, renewable energy
`digital`	Digital and cyber skills	Penetration testing, cloud architecture, data engineering, software development
`trade`	Modern building trades	Plastering, tiling, painting, decorating, modern roofing, insulation

Endangerment Registries

Endangerment status tags use a registry:status format. The registry namespace identifies the source; the status identifies the level.

Namespace	Registry	Status values
`hca`	Heritage Crafts Association Red List (UK)	`critically_endangered`, `endangered`, `at_risk`, `currently_viable`
`unesco`	UNESCO Intangible Cultural Heritage	`inscribed`, `urgent_safeguarding`, `best_practice`
`custom`	Any registry, self-describing	Free-form

Implementations MAY define additional registries for national or regional craft endangerment tracking (e.g. Japan's Living National Treasures, France's Compagnonnage, Germany's Meisterbrief system).

Protocol Flow

!Craft Skill and Technique Flow

sequenceDiagram
    participant Practitioner
    participant Relay
    participant Mentor
    participant Verifier
    participant Client

    Practitioner->>Relay: Publish Provider Profile (kind 30510)<br/>with craft:* extension tags
    Practitioner->>Relay: Publish Technique Records (kind 30401)
    Mentor->>Relay: Publish Mentorship Endorsement (kind 30517, NIP-TRUST)
    Note right of Mentor: endorsement_type: mentorship
    Verifier->>Relay: Publish Credential Attestation (kind 31000, NIP-VA)
    Note right of Verifier: third-party verification

    Client->>Relay: REQ {kinds:[30510], #t:["domain:metalwork"]}
    Relay-->>Client: Provider Profiles with craft:* tags
    Client->>Client: Post-filter by craft:proficiency, tradition, etc.
    Client->>Relay: REQ {kinds:[30401], authors:[practitioner]}
    Relay-->>Client: Technique Records
    Client->>Relay: Fetch mentorship + credential refs
    Relay-->>Client: Endorsements + Attestations

Discovery: Client queries for Provider Profiles by domain using relay-indexed #t filters, optionally combined with #g geohash filters.
Profile retrieval: Relay returns matching Provider Profiles. Craft-aware clients identify profiles with craft:* tags.
Client-side filtering: Client filters by craft:proficiency, craft:tradition, craft:endangerment, craft:available_for, or other craft-specific tags.
Cross-reference resolution: Client fetches linked mentorship endorsements (NIP-MENTORSHIP), credential attestations (NIP-REPUTATION), and scarcity signals (NIP-SCARCITY) via event reference tags.
Technique browsing: Client queries Technique Records by the practitioner's pubkey or by category/skill.
Technique retrieval: Relay returns Technique Records with structured content, media, and metadata.
Engagement: Client contacts the practitioner via any messaging or coordination protocol. NIP-CRAFTS does not prescribe a coordination layer.

Relationship to Existing NIPs

NIP-23 (Long-form Content)

NIP-23 (Long-form Content) is generic article publishing. Kind 30401 Technique Records carry structured craft-specific metadata (difficulty levels, tool and material requirements, safety warnings, prerequisite chains, endangerment status) that enables machine-readable discovery, progression tracking, and cross-referencing. A NIP-23 article cannot express prerequisite dependencies or endangerment registries in a relay-filterable way.

NIP-PROVIDER-PROFILES (Kind 30510)

Composition with NIP-PROVIDER-PROFILES is OPTIONAL. NIP-PROVIDER-PROFILES defines general-purpose provider profiles for service discovery. Craft practitioner identity composes directly with Provider Profiles using craft:* extension tags. This NIP does not define a separate Skill Profile kind; the Provider Profile is the canonical home for practitioner identity. See [Composing with NIP-PROVIDER-PROFILES](#composing-with-nip-provider-profiles) above for the full tag vocabulary and example.

NIP-MENTORSHIP (Kind 30517)

Composition with NIP-MENTORSHIP is OPTIONAL. NIP-MENTORSHIP defines mentorship endorsements via enriched NIP-TRUST Provider Endorsements. Provider Profiles with craft extensions MAY reference mentorship endorsements using the craft:mentorship_ref tag, linking a practitioner's training lineage to their declared skills. NIP-CRAFTS does not duplicate lineage tracking; that is NIP-MENTORSHIP's responsibility.

NIP-SCARCITY (Kind 30599)

Composition with NIP-SCARCITY is OPTIONAL. NIP-SCARCITY defines workforce and skill endangerment signals. Provider Profiles with craft extensions MAY reference scarcity signals using the craft:scarcity_signal tag, connecting an individual practitioner to broader endangerment data for their skills. The craft:endangerment tag on profiles and Technique Records provides a lightweight alternative for cases where no formal scarcity signal exists.

NIP-REPUTATION (NIP-VA kind 31000)

Composition with NIP-REPUTATION is OPTIONAL. NIP-REPUTATION defines Credential Attestations for third-party verification of qualifications. Provider Profiles with craft extensions MAY reference credential attestations using the craft:certification_ref tag, linking self-declared certifications to independently verified credentials. The craft:certification tag provides the self-declared reference; craft:certification_ref provides the verifiable attestation.

Security Considerations

Skill inflation. Self-declared proficiency levels carry no inherent trust. Implementations SHOULD cross-reference proficiency claims with mentorship endorsements (NIP-MENTORSHIP), credential attestations (NIP-REPUTATION), completed task history, and portfolio evidence. A master proficiency claim with no supporting credentials SHOULD be displayed with appropriate caveats.
False credentials. The craft:certification tag is a self-declared string. Implementations SHOULD verify certifications by checking for a corresponding craft:certification_ref linking to a NIP-REPUTATION Credential Attestation (NIP-VA kind 31000) from a recognised issuer. Unverified certifications SHOULD be displayed distinctly.
Taxonomy pollution. Custom categories enable extensibility but risk fragmentation. Implementations SHOULD normalise category values (lowercase, underscores) and present standard taxonomy categories preferentially in discovery interfaces.
Media integrity. Portfolio URLs and technique media are external references with no inherent integrity guarantees. Implementations SHOULD verify media availability and MAY use content-addressed storage (e.g. Blossom with hash-based URLs) for tamper evidence. Broken or altered media SHOULD be flagged.
Technique safety. Technique Records MAY contain safety-critical information. Implementations SHOULD prominently display craft:safety_notes and SHOULD NOT suppress or collapse safety information. Techniques without safety notes for inherently hazardous crafts (metalwork, chemical processes, working at height) SHOULD display a generic safety warning.
Restricted content. Some techniques should not be freely published (e.g. conservation methods that could enable theft, or procedures requiring supervised practice). Publishers SHOULD use NIP-44 encryption for restricted content and clearly indicate access restrictions.

Test Vectors

Kind 30510 with Craft Extensions - Skill Profile

{
  "kind": 30510,
  "pubkey": "a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2",
  "created_at": 1709740800,
  "tags": [
    ["d", "a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2_profile"],
    ["alt", "Craft practitioner profile: master blacksmith, architectural ironwork"],
    ["t", "domain:metalwork"],
    ["t", "skill:forge_work"],
    ["t", "skill:wrought_iron"],
    ["t", "credential:worshipful_company_blacksmiths:fellow"],
    ["domain", "metalwork"],
    ["skill", "forge_work"],
    ["skill", "wrought_iron"],
    ["credential", "worshipful_company_blacksmiths:fellow"],
    ["g", "gcp"],
    ["g", "gcpv"],
    ["coverage_geohash", "gcpvh"],
    ["craft:proficiency", "master"],
    ["craft:specialism", "architectural_ironwork"],
    ["craft:years_practising", "28"],
    ["craft:certification", "worshipful_company_blacksmiths:fellow"],
    ["craft:certification", "hetas:registered_installer"],
    ["craft:tradition", "english_ornamental_ironwork"],
    ["craft:endangerment", "hca:endangered"],
    ["craft:available_for", "commission"],
    ["craft:available_for", "teaching"],
    ["craft:location", "gcpvhd"],
    ["craft:workshop", "true"],
    ["craft:mentorship_ref", "dddd4444eeee5555ffff6666aaaa1111bbbb2222cccc3333dddd4444eeee5555", "wss://relay.example.com"],
    ["craft:certification_ref", "eeee5555ffff6666aaaa1111bbbb2222cccc3333dddd4444eeee5555ffff6666", "wss://relay.example.com"]
  ],
  "content": "Third-generation blacksmith working from a coal forge in the Cotswolds. I specialise in architectural ironwork for listed buildings.",
  "id": "<32-byte-hex>",
  "sig": "<64-byte-hex>"
}

Kind 30401 - Technique Record

{
  "kind": 30401,
  "pubkey": "b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3",
  "created_at": 1709740800,
  "tags": [
    ["d", "lime-pointing-flush-finish"],
    ["alt", "Technique record: Flush Lime Pointing with NHL 3.5"],
    ["craft:category", "building_conservation"],
    ["craft:skill", "lime_work"],
    ["craft:technique_name", "Flush Lime Pointing with NHL 3.5"],
    ["craft:difficulty", "intermediate"],
    ["craft:time_estimate", "PT4H"],
    ["craft:tools_required", "pointing trowel, hawk, jointing iron, spray bottle, stiff brush"],
    ["craft:materials_required", "NHL 3.5 lime putty, sharp sand (washed), clean water"],
    ["craft:tradition", "english_conservation"],
    ["craft:safety_notes", "Lime is caustic - wear nitrile gloves and eye protection. Wash skin contact immediately."],
    ["craft:seasonal_constraint", "frost_sensitive"],
    ["craft:media", "https://blossom.example.com/techniques/lime-pointing-step1.jpg"],
    ["craft:media_type", "image/jpeg"],
    ["craft:endangerment", "hca:at_risk"],
    ["license", "CC-BY-SA-4.0"],
    ["version", "1.2.0"],
    ["L", "craft:category"],
    ["l", "building_conservation", "craft:category"]
  ],
  "content": "## Flush Lime Pointing with NHL 3.5\n\nFlush pointing restores historic masonry joints using natural hydraulic lime, matching the original mortar profile. This technique is appropriate for most pre-1919 buildings with soft brick or stone.\n\n### Preparation\n\n1. Rake out existing joints to a minimum depth of 25mm.\n2. Brush out all loose material.\n3. Dampen joints thoroughly.\n\n### Mix\n\nRatio: 1 part NHL 3.5 to 2.5 parts sharp washed sand (by volume).\n\n### Application\n\n1. Push mix firmly into the joint, working bottom to top.\n2. Compact with a jointing iron.\n3. Finish flush with the masonry face.\n\n### Aftercare\n\nProtect from direct sun, wind, and frost for 72 hours minimum. Mist lightly with water twice daily in warm weather.",
  "id": "<32-byte-hex>",
  "sig": "<64-byte-hex>"
}

Dependencies

NIP-01: Basic protocol flow, addressable events
NIP-32: Labelling (category-based relay filtering)
NIP-40: Expiration timestamps (time-bounded profiles)
NIP-44: Versioned encrypted payloads (restricted technique content)
[NIP-PROVIDER-PROFILES](./NIP-PROVIDER-PROFILES.md): Service Provider Profiles (practitioner skill identity)

Reference Implementation

No public reference implementation exists yet. Implementors SHOULD refer to the kind definitions above.

A minimal implementation requires:

A Nostr client that supports addressable event publishing, NIP-32 label queries, and NIP-PROVIDER-PROFILES (kind 30510).
A technique browser that renders Markdown content with media references and safety notes.
Discovery logic that filters Provider Profiles by craft:* tags for craft-specific identity.