diff --git a/docs/agent-workflow.md b/docs/agent-workflow.md
index 10a6106..9824e4d 100644
--- a/docs/agent-workflow.md
+++ b/docs/agent-workflow.md
@@ -645,3 +645,56 @@ If `Edit` or `Write` (or another tool an execution agent needs) is missing from
 the target project's allowlist, the agent will report `TASK_BLOCKED` with an
 actionable error message explaining what permissions are needed. The user must
 update the project's permissions config before retrying.
+
+## Knowledge Base Tools
+
+### `get_knowledge_base`
+
+Returns all knowledge-base docs for a project in a single call. Used by
+planning, brainstorming, and debugging skills to load architectural context.
+
+**Input:**
+
+| Field     | Required | Description                               |
+| --------- | -------- | ----------------------------------------- |
+| `project` | yes      | Project name                              |
+| `repo`    | no       | Repo name; defaults to the primary repo   |
+
+**Response:**
+
+```json
+{
+  "project": "my-project",
+  "repo": "primary",
+  "docs": {
+    "architecture.md": "...",
+    "code-structure.md": "...",
+    "api-documentation.md": "...",
+    "glossary.md": "..."
+  },
+  "summaries": {
+    "architecture.md": "Short summary extracted from the doc's ## Summary section.",
+    "code-structure.md": "Short summary...",
+    "api-documentation.md": "",
+    "glossary.md": "Short summary..."
+  },
+  "meta": { "...": "..." }
+}
+```
+
+**`summaries` field:** a map from doc name to the text of its first `## Summary`
+section. Empty string when a doc has no `## Summary` section. Always present
+(never `null`) — an empty object `{}` means no docs have summaries yet.
+
+**Usage pattern for agents:** when `summaries` is non-empty, read each doc's
+summary to judge relevance to the current task, then retain full content from
+`docs` only for the relevant docs. When `summaries` is empty or a doc has no
+entry, load all docs as before (current fallback behaviour).
+
+### `read_knowledge_doc`
+
+Read a single KB doc by name. Use when you need only one doc and want to avoid
+loading the full payload.
+
+**Input:** `project` (required), `repo` (optional), `doc` (required — one of
+`architecture.md`, `code-structure.md`, `api-documentation.md`, `glossary.md`).
diff --git a/internal/mcp/tools.go b/internal/mcp/tools.go
index 2982a9f..26c64c8 100644
--- a/internal/mcp/tools.go
+++ b/internal/mcp/tools.go
@@ -1206,10 +1206,11 @@ type getKnowledgeBaseInput struct {
 }
 
 type getKnowledgeBaseOutput struct {
-	Project string                  `json:"project"`
-	Repo    string                  `json:"repo"`
-	Docs    map[string]string       `json:"docs"`
-	Meta    board.KnowledgeRepoMeta `json:"meta"`
+	Project   string                  `json:"project"`
+	Repo      string                  `json:"repo"`
+	Docs      map[string]string       `json:"docs"`
+	Summaries map[string]string       `json:"summaries"`
+	Meta      board.KnowledgeRepoMeta `json:"meta"`
 }
 
 func registerGetKnowledgeBase(server *mcp.Server, svc *service.CardService) {
@@ -1227,15 +1228,20 @@ func registerGetKnowledgeBase(server *mcp.Server, svc *service.CardService) {
 			out.Docs = map[string]string{}
 		}
 
+		if out.Summaries == nil {
+			out.Summaries = map[string]string{}
+		}
+
 		if out.Meta.Docs == nil {
 			out.Meta.Docs = map[string]board.KnowledgeDocMeta{}
 		}
 
 		return nil, getKnowledgeBaseOutput{
-			Project: out.Project,
-			Repo:    out.Repo,
-			Docs:    out.Docs,
-			Meta:    out.Meta,
+			Project:   out.Project,
+			Repo:      out.Repo,
+			Docs:      out.Docs,
+			Summaries: out.Summaries,
+			Meta:      out.Meta,
 		}, nil
 	})
 }
diff --git a/internal/service/service_knowledge.go b/internal/service/service_knowledge.go
index 52c0087..3ebd99f 100644
--- a/internal/service/service_knowledge.go
+++ b/internal/service/service_knowledge.go
@@ -237,10 +237,43 @@ func (s *CardService) WriteKnowledgeDocs(ctx context.Context, in WriteKnowledgeD
 
 // KnowledgeBaseRead is returned by ReadKnowledgeBase.
 type KnowledgeBaseRead struct {
-	Project string                  `json:"project"`
-	Repo    string                  `json:"repo"`
-	Docs    map[string]string       `json:"docs"`
-	Meta    board.KnowledgeRepoMeta `json:"meta"`
+	Project   string                  `json:"project"`
+	Repo      string                  `json:"repo"`
+	Docs      map[string]string       `json:"docs"`
+	Summaries map[string]string       `json:"summaries"`
+	Meta      board.KnowledgeRepoMeta `json:"meta"`
+}
+
+// extractSummary returns the text content of the first ## Summary section in
+// the given markdown content. It scans for the first line that is exactly
+// "## Summary", collects all following lines until the next ##-level heading
+// or EOF, then returns the trimmed result. Returns an empty string if no
+// ## Summary section is found.
+func extractSummary(content string) string {
+	lines := strings.Split(content, "\n")
+
+	inSummary := false
+
+	var summaryLines []string
+
+	for _, line := range lines {
+		if !inSummary {
+			if line == "## Summary" {
+				inSummary = true
+			}
+
+			continue
+		}
+
+		// Stop at the next ##-level heading.
+		if strings.HasPrefix(line, "## ") {
+			break
+		}
+
+		summaryLines = append(summaryLines, line)
+	}
+
+	return strings.TrimSpace(strings.Join(summaryLines, "\n"))
 }
 
 // KnowledgeDocRead is returned by ReadKnowledgeDoc.
@@ -319,7 +352,7 @@ func (s *CardService) ReadKnowledgeBase(ctx context.Context, project, repo strin
 		// primary, store I/O) must propagate so callers see the real
 		// failure.
 		if errors.Is(err, errNoReposConfigured) {
-			return &KnowledgeBaseRead{Project: project, Docs: map[string]string{}}, nil
+			return &KnowledgeBaseRead{Project: project, Docs: map[string]string{}, Summaries: map[string]string{}}, nil
 		}
 
 		return nil, err
@@ -331,6 +364,7 @@ func (s *CardService) ReadKnowledgeBase(ctx context.Context, project, repo strin
 	}
 
 	docs := map[string]string{}
+	summaries := map[string]string{}
 
 	for _, name := range board.KnowledgeDocNames {
 		exists, err := s.store.KnowledgeDocExists(ctx, project, resolvedRepo, name)
@@ -348,13 +382,15 @@ func (s *CardService) ReadKnowledgeBase(ctx context.Context, project, repo strin
 		}
 
 		docs[name] = string(data)
+		summaries[name] = extractSummary(string(data))
 	}
 
 	return &KnowledgeBaseRead{
-		Project: project,
-		Repo:    resolvedRepo,
-		Docs:    docs,
-		Meta:    meta.Repos[resolvedRepo],
+		Project:   project,
+		Repo:      resolvedRepo,
+		Docs:      docs,
+		Summaries: summaries,
+		Meta:      meta.Repos[resolvedRepo],
 	}, nil
 }
 
diff --git a/internal/service/service_knowledge_test.go b/internal/service/service_knowledge_test.go
index db1e65b..f0bdcc9 100644
--- a/internal/service/service_knowledge_test.go
+++ b/internal/service/service_knowledge_test.go
@@ -568,6 +568,93 @@ func TestWriteKnowledgeDocs_InvalidDocNameReturnsSentinel(t *testing.T) {
 	assert.ErrorIs(t, err, storage.ErrInvalidKnowledgeDoc)
 }
 
+func TestExtractSummary(t *testing.T) {
+	tests := []struct {
+		name     string
+		content  string
+		expected string
+	}{
+		{
+			name: "well-formed doc with summary section",
+			content: `# Architecture
+
+## Summary
+This document describes the system architecture.
+It covers components and data flow.
+
+## Components
+Details here.
+`,
+			expected: "This document describes the system architecture.\nIt covers components and data flow.",
+		},
+		{
+			name:     "doc missing summary section",
+			content:  "# No Summary Here\n\n## Components\nDetails.\n",
+			expected: "",
+		},
+		{
+			name: "summary followed by next section stops at heading",
+			content: `## Summary
+First summary line.
+Second summary line.
+## NextSection
+Should not be included.
+`,
+			expected: "First summary line.\nSecond summary line.",
+		},
+		{
+			name: "two summary headings returns first one only",
+			content: `## Summary
+First summary content.
+
+## Other
+## Summary
+Second summary content should be ignored.
+`,
+			expected: "First summary content.",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := extractSummary(tc.content)
+			assert.Equal(t, tc.expected, got)
+		})
+	}
+}
+
+func TestReadKnowledgeBase_PopulatesSummaries(t *testing.T) {
+	svc, _, cleanup := setupTest(t)
+	defer cleanup()
+
+	ctx := context.Background()
+	content := "# Architecture\n\n## Summary\nBrief description of the architecture.\n\n## Details\nMore here.\n"
+
+	_, err := svc.WriteKnowledgeDocs(ctx, WriteKnowledgeDocsInput{
+		Project:    "test-project",
+		Repo:       "core",
+		Docs:       map[string]string{"architecture.md": content},
+		Source:     KnowledgeWriteSourceRefresh,
+		HeadCommit: "abc",
+		AgentID:    "human:t",
+	})
+	require.NoError(t, err)
+
+	out, err := svc.ReadKnowledgeBase(ctx, "test-project", "core")
+	require.NoError(t, err)
+	assert.NotNil(t, out.Summaries)
+	assert.Equal(t, "Brief description of the architecture.", out.Summaries["architecture.md"])
+}
+
+func TestReadKnowledgeBase_SummariesNonNilWhenEmpty(t *testing.T) {
+	svc, _, cleanup := setupTest(t)
+	defer cleanup()
+
+	out, err := svc.ReadKnowledgeBase(context.Background(), "test-project", "")
+	require.NoError(t, err)
+	assert.NotNil(t, out.Summaries, "Summaries must be non-nil even when no docs exist")
+}
+
 func TestBuildRefreshPlan_ReasonsOnlyMissingOrScheduled(t *testing.T) {
 	svc, _, cleanup := setupTest(t)
 	defer cleanup()
diff --git a/workflow-skills/brainstorming.md b/workflow-skills/brainstorming.md
index c791f92..92d3cf1 100644
--- a/workflow-skills/brainstorming.md
+++ b/workflow-skills/brainstorming.md
@@ -98,6 +98,12 @@ You MUST complete each of these in order:
    `glossary.md` to use the project's vocabulary correctly. Reference
    them when discussing architecture, decomposition, or naming. If
    empty, note that to the user when relevant and proceed.
+
+   If `summaries` is non-empty, use each doc's summary to judge
+   relevance to the current task before loading its full content from
+   `docs`. Retain in active context only the docs whose summary
+   indicates relevance. If `summaries` is empty or a doc has no entry,
+   load all docs.
 2. **Explore project context** — read files referenced in the card and
    anything the KB doesn't cover (recent commits, files mentioned in
    the body). Don't re-derive what the KB already states.
diff --git a/workflow-skills/create-plan.md b/workflow-skills/create-plan.md
index decf503..794da20 100644
--- a/workflow-skills/create-plan.md
+++ b/workflow-skills/create-plan.md
@@ -186,6 +186,12 @@ Hold this claim through Phase 5.
    `glossary.md` to use the project's vocabulary correctly. If empty,
    proceed.
 
+   If `summaries` is non-empty, use each doc's summary to judge
+   relevance to the current task before loading its full content from
+   `docs`. Retain in active context only the docs whose summary
+   indicates relevance. If `summaries` is empty or a doc has no entry,
+   load all docs.
+
 2. **Review card details.** Read the card details provided above. If
    the card body already contains a `## Plan` section, use it as a
    starting point — do not discard previous planning work. Only call
diff --git a/workflow-skills/refresh-knowledge.md b/workflow-skills/refresh-knowledge.md
index b920f4b..5934e0a 100644
--- a/workflow-skills/refresh-knowledge.md
+++ b/workflow-skills/refresh-knowledge.md
@@ -205,6 +205,8 @@ via the Task tool. Pass:
 
 Collect each sub-agent's output as the new doc content.
 
+Every generated doc MUST begin with `## Summary` as its first level-2 heading (150–300 tokens, prose describing the doc's purpose and major sections).
+
 After each sub-agent returns, call `update_refresh_progress` so the UI
 shows progress:
 
@@ -241,6 +243,10 @@ in local mode (no UI-side job to update) — proceed regardless.
 ```markdown
 # System Architecture
 
+## Summary
+
+[150–300 token prose paragraph: what this doc covers, what questions it answers, and the major sections inside — written for an agent deciding which full docs to load into context.]
+
 ## System Overview
 
 [2-4 paragraph high-level description of what the system does, who calls
@@ -296,6 +302,10 @@ where it is enforced so the agent can verify before changing nearby code.]
 ```markdown
 # Code Structure
 
+## Summary
+
+[150–300 token prose paragraph: what this doc covers, what questions it answers, and the major sections inside — written for an agent deciding which full docs to load into context.]
+
 ## Build System
 
 - **Type**: [go modules / npm / pyproject / cargo / make-driven / etc.]
@@ -357,6 +367,10 @@ without REST/MCP/CLI). Note the skip in your output to the user.
 ```markdown
 # API Documentation
 
+## Summary
+
+[150–300 token prose paragraph: what this doc covers, what questions it answers, and the major sections inside — written for an agent deciding which full docs to load into context.]
+
 ## Overview
 
 [Which surfaces this repo exposes: REST, MCP, CLI, gRPC, webhooks. Where
@@ -412,6 +426,10 @@ each is registered in the codebase.]
 ```markdown
 # Glossary
 
+## Summary
+
+[150–300 token prose paragraph: what this doc covers, what questions it answers, and the major sections inside — written for an agent deciding which full docs to load into context.]
+
 ## Domain terms
 
 ### [Term]
diff --git a/workflow-skills/run-autonomous.md b/workflow-skills/run-autonomous.md
index f8aa1bc..4bf6137 100644
--- a/workflow-skills/run-autonomous.md
+++ b/workflow-skills/run-autonomous.md
@@ -80,6 +80,11 @@ If docs are returned, hold them in your reasoning context: use
 boundaries, `api-documentation.md` to avoid breaking public surfaces, and
 `glossary.md` to use the project's vocabulary correctly. If empty, proceed.
 
+If `summaries` is non-empty, use each doc's summary to judge relevance to the
+current task before loading its full content from `docs`. Retain in active
+context only the docs whose summary indicates relevance. If `summaries` is
+empty or a doc has no entry, load all docs.
+
 Immediately after the KB call, log the outcome:
 
 ```
diff --git a/workflow-skills/systematic-debugging.md b/workflow-skills/systematic-debugging.md
index eff97f8..f6c1dd4 100644
--- a/workflow-skills/systematic-debugging.md
+++ b/workflow-skills/systematic-debugging.md
@@ -79,6 +79,11 @@ You MUST complete each phase before proceeding to the next.
      - Translate user-facing names to internal names (`glossary.md`).
    - If empty, proceed without — fall back to grepping for symbols and
      reading `CLAUDE.md`.
+   - If `summaries` is non-empty, use each doc's summary to judge
+     relevance to the current bug before loading its full content from
+     `docs`. Retain in active context only the docs whose summary
+     indicates relevance. If `summaries` is empty or a doc has no
+     entry, load all docs.
 
 2. **Read the card body carefully.**
    - Quote any stack traces, error messages, error codes, or log lines the