diff --git a/.github/skills/add-community-extension/SKILL.md b/.github/skills/add-community-extension/SKILL.md
index 4d56eaa9d0..179c11b3e2 100644
--- a/.github/skills/add-community-extension/SKILL.md
+++ b/.github/skills/add-community-extension/SKILL.md
@@ -70,6 +70,8 @@ Use the existing entries as the format template. Required fields:
     "documentation": "<documentation>",
     "changelog": "<changelog>",
     "license": "<license>",
+    "category": "<category>",
+    "effect": "<effect>",
     "requires": {
       "speckit_version": "<speckit_version>"
     },
@@ -87,6 +89,9 @@ Use the existing entries as the format template. Required fields:
 }
 ```
 
+**Category** — free-form string; common values: `docs`, `code`, `process`, `integration`, `visibility`
+**Effect** — one of: `read-only`, `read-write`
+
 If the extension has optional tool dependencies, add a `"tools"` array inside `"requires"`:
 
 ```json
@@ -113,8 +118,8 @@ Determine the category and effect from the extension's behavior:
 | <Name> | <Description> | `<category>` | <Effect> | [<repo-name>](<repository-url>) |
 ```
 
-**Category** — one of: `docs`, `code`, `process`, `integration`, `visibility`
-**Effect** — `Read-only` (produces reports only) or `Read+Write` (modifies project files)
+**Category** — free-form; common values: `docs`, `code`, `process`, `integration`, `visibility`
+**Effect** — write canonical values `read-only` or `read-write` in `extension.yml` and `catalog.community.json`; use `Read-only`/`Read+Write` only for the docs table display
 
 ### 6. Commit, push, and open PR
 
diff --git a/docs/community/extensions.md b/docs/community/extensions.md
index 8d41db95c6..517c32290f 100644
--- a/docs/community/extensions.md
+++ b/docs/community/extensions.md
@@ -7,7 +7,7 @@
 
 The following community-contributed extensions are available in [`catalog.community.json`](https://github.com/github/spec-kit/blob/main/extensions/catalog.community.json):
 
-**Categories:**
+**Categories** (common values, but any string is allowed):
 
 - `docs` — reads, validates, or generates spec artifacts
 - `code` — reviews, validates, or modifies source code
@@ -15,10 +15,13 @@ The following community-contributed extensions are available in [`catalog.commun
 - `integration` — syncs with external platforms
 - `visibility` — reports on project health or progress
 
-**Effect:**
+**Effect** (canonical `extension.yml`/catalog values):
 
-- `Read-only` — produces reports without modifying files
-- `Read+Write` — modifies files, creates artifacts, or updates specs
+- `read-only` — produces reports without modifying files (displayed as `Read-only` in the table)
+- `read-write` — modifies files, creates artifacts, or updates specs (displayed as `Read+Write` in the table)
+
+> [!TIP]
+> Extension authors can declare `category` and `effect` in their `extension.yml` under the `extension:` block. These fields are also available in `catalog.community.json` for tooling and the CLI (`specify extension info`).
 
 | Extension | Purpose | Category | Effect | URL |
 |-----------|---------|----------|--------|-----|
diff --git a/extensions/catalog.community.json b/extensions/catalog.community.json
index 07fb7ef55d..b3ff5e3b3c 100644
--- a/extensions/catalog.community.json
+++ b/extensions/catalog.community.json
@@ -15,6 +15,8 @@
       "documentation": "https://github.com/mnriem/spec-kit-extensions/blob/main/aide/README.md",
       "changelog": "https://github.com/mnriem/spec-kit-extensions/blob/main/aide/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.2.0"
       },
@@ -48,6 +50,8 @@
       "documentation": "https://github.com/xymelon/spec-kit-agent-assign/blob/main/README.md",
       "changelog": "https://github.com/xymelon/spec-kit-agent-assign/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -80,6 +84,8 @@
       "documentation": "https://github.com/bigsmartben/spec-kit-agent-governance/blob/main/README.md",
       "changelog": "https://github.com/bigsmartben/spec-kit-agent-governance/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.8.0",
         "tools": [
@@ -117,6 +123,8 @@
       "documentation": "https://github.com/pragya247/spec-kit-orchestrator/blob/main/README.md",
       "changelog": "https://github.com/pragya247/spec-kit-orchestrator/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.6.1"
       },
@@ -149,6 +157,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-api-evolve/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-api-evolve/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -186,6 +196,8 @@
       "documentation": "https://github.com/bigsmartben/spec-kit-arch/blob/main/README.md",
       "changelog": "https://github.com/bigsmartben/spec-kit-arch/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.8.10.dev0"
       },
@@ -217,6 +229,8 @@
       "documentation": "https://github.com/UmmeHabiba1312/spec-kit-architect-preview/blob/main/README.md",
       "changelog": "https://github.com/UmmeHabiba1312/spec-kit-architect-preview/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "visibility",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -249,6 +263,8 @@
       "documentation": "https://github.com/DyanGalih/spec-kit-architecture-guard/blob/main/docs/architecture-overview.md",
       "changelog": "https://github.com/DyanGalih/spec-kit-architecture-guard/releases",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -283,6 +299,8 @@
       "documentation": "https://github.com/stn1slv/spec-kit-archive/blob/main/README.md",
       "changelog": "https://github.com/stn1slv/spec-kit-archive/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -314,6 +332,8 @@
       "documentation": "https://github.com/pragya247/spec-kit-azure-devops/blob/main/README.md",
       "changelog": "https://github.com/pragya247/spec-kit-azure-devops/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0",
         "tools": [
@@ -353,6 +373,8 @@
       "documentation": "https://github.com/chordpli/spec-kit-blueprint/blob/main/README.md",
       "changelog": "https://github.com/chordpli/spec-kit-blueprint/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.2.0"
       },
@@ -385,6 +407,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-branch-convention/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-branch-convention/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -417,6 +441,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-brownfield/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-brownfield/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -438,7 +464,7 @@
       "updated_at": "2026-04-10T00:00:00Z"
     },
     "brownkit": {
-      "name": "BrownKit \u2014 Brownfield Discovery for Spec-Kit",
+      "name": "BrownKit — Brownfield Discovery for Spec-Kit",
       "id": "brownkit",
       "description": "Evidence-driven capability discovery, security and QA risk assessment for existing codebases.",
       "author": "Maksim Shautsou",
@@ -449,6 +475,8 @@
       "documentation": "https://github.com/MaksimShevtsov/BrownKit/blob/main/README.md",
       "changelog": "https://github.com/MaksimShevtsov/BrownKit/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -481,6 +509,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-bugfix/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-bugfix/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -513,6 +543,8 @@
       "documentation": "https://github.com/maximiliamus/spec-kit-canon/blob/master/README.md",
       "changelog": "https://github.com/maximiliamus/spec-kit-canon/blob/master/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.3"
       },
@@ -548,6 +580,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-catalog-ci/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-catalog-ci/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -580,6 +614,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-changelog/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-changelog/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -612,6 +648,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-ci-guard/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-ci-guard/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -645,6 +683,8 @@
       "documentation": "https://github.com/aaronrsun/spec-kit-checkpoint/blob/main/README.md",
       "changelog": "https://github.com/aaronrsun/spec-kit-checkpoint/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "code",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -674,6 +714,8 @@
       "documentation": "https://github.com/dsrednicki/spec-kit-cleanup/blob/main/README.md",
       "changelog": "https://github.com/dsrednicki/spec-kit-cleanup/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "code",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -706,6 +748,8 @@
       "documentation": "https://github.com/twbrandon7/spec-kit-conduct-ext/blob/main/README.md",
       "changelog": "https://github.com/twbrandon7/spec-kit-conduct-ext/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.1"
       },
@@ -736,6 +780,8 @@
       "documentation": "https://github.com/arunt14/spec-kit-critique/blob/main/README.md",
       "changelog": "https://github.com/arunt14/spec-kit-critique/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -766,6 +812,8 @@
       "documentation": "https://github.com/aaronrsun/spec-kit-confluence/blob/main/README.md",
       "changelog": "https://github.com/aaronrsun/spec-kit-confluence/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -794,6 +842,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-cost/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-cost/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "visibility",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.8.0"
       },
@@ -826,6 +876,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-diagram-/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-diagram-/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "visibility",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -858,6 +910,8 @@
       "documentation": "https://github.com/raccioly/docguard/blob/main/extensions/spec-kit-docguard/README.md",
       "changelog": "https://github.com/raccioly/docguard/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0",
         "tools": [
@@ -900,6 +954,8 @@
       "documentation": "https://github.com/KhawarHabibKhan/spec-kit-doctor/blob/main/README.md",
       "changelog": "https://github.com/KhawarHabibKhan/spec-kit-doctor/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "visibility",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -931,6 +987,8 @@
       "documentation": "https://github.com/mnriem/spec-kit-extensions/blob/main/extensify/README.md",
       "changelog": "https://github.com/mnriem/spec-kit-extensions/blob/main/extensify/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.8.0"
       },
@@ -962,6 +1020,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-fix-findings/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-fix-findings/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "code",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -994,6 +1054,8 @@
       "documentation": "https://github.com/speckit-community/spec-kit-fixit/blob/main/README.md",
       "changelog": "https://github.com/speckit-community/spec-kit-fixit/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "code",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1025,6 +1087,8 @@
       "documentation": "https://github.com/sharathsatish/spec-kit-fleet/blob/main/README.md",
       "changelog": "https://github.com/sharathsatish/spec-kit-fleet/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1055,6 +1119,8 @@
       "homepage": "https://github.com/RogerBestMsft/spec-kit-FxToNet",
       "documentation": "https://github.com/RogerBestMsft/spec-kit-FxToNet/blob/main/README.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0",
         "tools": [
@@ -1094,6 +1160,8 @@
       "documentation": "https://github.com/Fatima367/spec-kit-github-issues/blob/main/README.md",
       "changelog": "https://github.com/Fatima367/spec-kit-github-issues/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0",
         "tools": [
@@ -1134,6 +1202,8 @@
       "documentation": "https://github.com/aaronrsun/spec-kit-issue/blob/main/README.md",
       "changelog": "https://github.com/aaronrsun/spec-kit-issue/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1166,6 +1236,8 @@
       "documentation": "https://github.com/imviancagrace/spec-kit-iterate/blob/main/README.md",
       "changelog": "https://github.com/imviancagrace/spec-kit-iterate/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1196,6 +1268,8 @@
       "documentation": "https://github.com/mbachorik/spec-kit-jira/blob/main/README.md",
       "changelog": "https://github.com/mbachorik/spec-kit-jira/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1227,6 +1301,8 @@
       "documentation": "https://github.com/imviancagrace/spec-kit-learn/blob/main/README.md",
       "changelog": "https://github.com/imviancagrace/spec-kit-learn/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "docs",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1258,6 +1334,8 @@
       "documentation": "https://github.com/ashbrener/spec-kit-linear/blob/main/README.md",
       "changelog": "https://github.com/ashbrener/spec-kit-linear/releases",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0"
       },
@@ -1291,6 +1369,8 @@
       "documentation": "https://github.com/BenBtg/spec-kit-m365/blob/main/README.md",
       "changelog": "https://github.com/BenBtg/spec-kit-m365/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.1.0",
         "tools": [
@@ -1329,6 +1409,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-ext/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-ext/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1362,6 +1444,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-azure-devops/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-azure-devops/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1394,6 +1478,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-ci/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-ci/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1427,6 +1513,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-github-projects/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-github-projects/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1459,6 +1547,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-jira/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-jira/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1491,6 +1581,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-linear/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-linear/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1523,6 +1615,8 @@
       "documentation": "https://github.com/GenieRobot/spec-kit-maqa-trello/blob/main/README.md",
       "changelog": "https://github.com/GenieRobot/spec-kit-maqa-trello/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.3.0"
       },
@@ -1555,6 +1649,8 @@
       "documentation": "https://github.com/BenBtg/spec-kit-markitdown/blob/main/README.md",
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       "documentation": "https://github.com/KevinBrown5280/spec-kit-version-guard/blob/main/README.md",
       "changelog": "https://github.com/KevinBrown5280/spec-kit-version-guard/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.2.0"
       },
@@ -3445,6 +3651,8 @@
       "homepage": "https://github.com/DevAbdullah90/spec-kit-whatif",
       "documentation": "https://github.com/DevAbdullah90/spec-kit-whatif/blob/main/README.md",
       "license": "MIT",
+      "category": "visibility",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.6.0"
       },
@@ -3475,6 +3683,8 @@
       "documentation": "https://github.com/TortoiseWolfe/spec-kit-extension-wireframe/blob/main/README.md",
       "changelog": "https://github.com/TortoiseWolfe/spec-kit-extension-wireframe/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "visibility",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.6.0"
       },
@@ -3510,6 +3720,8 @@
       "documentation": "https://github.com/sakitA/spec-kit-workiq/blob/main/README.md",
       "changelog": "https://github.com/sakitA/spec-kit-workiq/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "integration",
+      "effect": "read-only",
       "requires": {
         "speckit_version": ">=0.1.0",
         "tools": [
@@ -3554,6 +3766,8 @@
       "documentation": "https://github.com/Quratulain-bilal/spec-kit-worktree/blob/main/README.md",
       "changelog": "https://github.com/Quratulain-bilal/spec-kit-worktree/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -3586,6 +3800,8 @@
       "documentation": "https://github.com/dango85/spec-kit-worktree-parallel/blob/main/README.md",
       "changelog": "https://github.com/dango85/spec-kit-worktree-parallel/blob/main/CHANGELOG.md",
       "license": "MIT",
+      "category": "process",
+      "effect": "read-write",
       "requires": {
         "speckit_version": ">=0.4.0"
       },
@@ -3607,4 +3823,4 @@
       "updated_at": "2026-04-13T00:00:00Z"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/extensions/template/extension.yml b/extensions/template/extension.yml
index b907e0c786..a23bdc87da 100644
--- a/extensions/template/extension.yml
+++ b/extensions/template/extension.yml
@@ -13,6 +13,14 @@ extension:
   # CUSTOMIZE: Brief description (under 200 characters)
   description: "Brief description of what your extension does"
 
+  # CUSTOMIZE: Extension category — describes what the extension operates on
+  # Common values: docs, code, process, integration, visibility
+  # category: "process"
+
+  # CUSTOMIZE: Extension effect — whether it modifies project files
+  # One of: read-only | read-write
+  # effect: "read-write"
+
   # CUSTOMIZE: Your name or organization name
   author: "Your Name"
 
diff --git a/src/specify_cli/__init__.py b/src/specify_cli/__init__.py
index 23d31cb0cf..96a65e5e9f 100644
--- a/src/specify_cli/__init__.py
+++ b/src/specify_cli/__init__.py
@@ -1983,7 +1983,11 @@ def extension_info(
             author = ext_manifest.data.get("extension", {}).get("author")
             if author:
                 console.print(f"[dim]Author:[/dim] {author}")
-                console.print()
+            if ext_manifest.category:
+                console.print(f"[dim]Category:[/dim] {ext_manifest.category}")
+            if ext_manifest.effect:
+                console.print(f"[dim]Effect:[/dim] {ext_manifest.effect}")
+            console.print()
 
             if ext_manifest.commands:
                 console.print("[bold]Commands:[/bold]")
@@ -2033,6 +2037,12 @@ def _print_extension_info(ext_info: dict, manager):
     console.print(f"[dim]Author:[/dim] {ext_info.get('author', 'Unknown')}")
     console.print(f"[dim]License:[/dim] {ext_info.get('license', 'Unknown')}")
 
+    # Category and Effect
+    if ext_info.get('category'):
+        console.print(f"[dim]Category:[/dim] {ext_info['category']}")
+    if ext_info.get('effect'):
+        console.print(f"[dim]Effect:[/dim] {ext_info['effect']}")
+
     # Source catalog
     if ext_info.get("_catalog_name"):
         install_allowed = ext_info.get("_install_allowed", True)
diff --git a/src/specify_cli/extensions.py b/src/specify_cli/extensions.py
index adbbedcb94..daf009e4b0 100644
--- a/src/specify_cli/extensions.py
+++ b/src/specify_cli/extensions.py
@@ -41,6 +41,8 @@
 })
 EXTENSION_COMMAND_NAME_PATTERN = re.compile(r"^speckit\.([a-z0-9-]+)\.([a-z0-9-]+)$")
 
+VALID_EFFECTS = frozenset({"read-only", "read-write"})
+
 DEFAULT_HOOK_PRIORITY = 10
 
 REINSTALL_COMMAND = "uv tool install specify-cli --force --from git+https://github.com/github/spec-kit.git"
@@ -201,6 +203,21 @@ def _validate(self):
         except pkg_version.InvalidVersion:
             raise ValidationError(f"Invalid version: {ext['version']}")
 
+        # Validate optional category field (free-form string)
+        if "category" in ext:
+            if not isinstance(ext["category"], str) or not ext["category"].strip():
+                raise ValidationError(
+                    "Invalid extension.category: must be a non-empty string"
+                )
+
+        # Validate optional effect field
+        if "effect" in ext:
+            if not isinstance(ext["effect"], str) or ext["effect"] not in VALID_EFFECTS:
+                raise ValidationError(
+                    f"Invalid extension.effect '{ext.get('effect')}': "
+                    f"must be one of {sorted(VALID_EFFECTS)}"
+                )
+
         # Validate requires section
         requires = self.data["requires"]
         if "speckit_version" not in requires:
@@ -374,6 +391,16 @@ def description(self) -> str:
         """Get extension description."""
         return self.data["extension"]["description"]
 
+    @property
+    def category(self) -> Optional[str]:
+        """Get extension category (free-form; common values: docs, code, process, integration, visibility)."""
+        return self.data["extension"].get("category")
+
+    @property
+    def effect(self) -> Optional[str]:
+        """Get extension effect (read-only, read-write)."""
+        return self.data["extension"].get("effect")
+
     @property
     def requires_speckit_version(self) -> str:
         """Get required spec-kit version range."""
diff --git a/tests/test_extensions.py b/tests/test_extensions.py
index dd231de311..d8cd0bcbe6 100644
--- a/tests/test_extensions.py
+++ b/tests/test_extensions.py
@@ -24,6 +24,7 @@
     CatalogEntry,
     CORE_COMMAND_NAMES,
     DEFAULT_HOOK_PRIORITY,
+    VALID_EFFECTS,
     ExtensionManifest,
     ExtensionRegistry,
     ExtensionManager,
@@ -300,6 +301,69 @@ def test_invalid_version(self, temp_dir, valid_manifest_data):
         with pytest.raises(ValidationError, match="Invalid version"):
             ExtensionManifest(manifest_path)
 
+    def test_valid_category(self, temp_dir, valid_manifest_data):
+        """Test manifest with various category values (free-form string)."""
+        import yaml
+
+        for category in ("docs", "code", "process", "integration", "visibility", "custom-category"):
+            valid_manifest_data["extension"]["category"] = category
+            manifest_path = temp_dir / "extension.yml"
+            with open(manifest_path, 'w') as f:
+                yaml.dump(valid_manifest_data, f)
+            manifest = ExtensionManifest(manifest_path)
+            assert manifest.category == category
+
+    def test_valid_effect(self, temp_dir, valid_manifest_data):
+        """Test manifest with valid effect values."""
+        import yaml
+
+        for effect in sorted(VALID_EFFECTS):
+            valid_manifest_data["extension"]["effect"] = effect
+            manifest_path = temp_dir / "extension.yml"
+            with open(manifest_path, 'w') as f:
+                yaml.dump(valid_manifest_data, f)
+            manifest = ExtensionManifest(manifest_path)
+            assert manifest.effect == effect
+
+    def test_invalid_category(self, temp_dir, valid_manifest_data):
+        """Test manifest with empty category raises ValidationError."""
+        import yaml
+
+        valid_manifest_data["extension"]["category"] = ""
+        manifest_path = temp_dir / "extension.yml"
+        with open(manifest_path, 'w') as f:
+            yaml.dump(valid_manifest_data, f)
+
+        with pytest.raises(ValidationError, match="Invalid extension.category"):
+            ExtensionManifest(manifest_path)
+
+    def test_invalid_effect(self, temp_dir, valid_manifest_data):
+        """Test manifest with invalid effect raises ValidationError."""
+        import yaml
+
+        valid_manifest_data["extension"]["effect"] = "write-only"
+        manifest_path = temp_dir / "extension.yml"
+        with open(manifest_path, 'w') as f:
+            yaml.dump(valid_manifest_data, f)
+
+        with pytest.raises(ValidationError, match="Invalid extension.effect"):
+            ExtensionManifest(manifest_path)
+
+    def test_category_and_effect_optional(self, temp_dir, valid_manifest_data):
+        """Test that omitting category and effect still passes validation."""
+        import yaml
+
+        # Ensure no category/effect in data
+        valid_manifest_data["extension"].pop("category", None)
+        valid_manifest_data["extension"].pop("effect", None)
+        manifest_path = temp_dir / "extension.yml"
+        with open(manifest_path, 'w') as f:
+            yaml.dump(valid_manifest_data, f)
+
+        manifest = ExtensionManifest(manifest_path)
+        assert manifest.category is None
+        assert manifest.effect is None
+
     def test_invalid_command_name(self, temp_dir, valid_manifest_data):
         """Test manifest with command name that cannot be auto-corrected raises ValidationError."""
         import yaml