memory

package
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 Go to latest Published: May 19, 2026 License: MIT Imports: 11 Imported by: 0

Documentation

Overview

Package memory provides persistent, agent-managed memory across sessions.

Architecture

Three tiers:

  1. Facts — Two typed files (user.md, env.md) with character caps, injected into the system prompt as a frozen snapshot. Managed by the agent via the memory tool (add/replace/remove/consolidate/read).

  2. Buffer — In-memory ring buffer on the Session struct. One-line summaries appended after each turn. Injected only when non-empty.

  3. Episodes — LLM-extracted durable facts written after sessions with ≥3 turns. Searchable via memory(search=...).

Merge-on-Write

When adding a fact, go-vector's RandomProjections provides a fast similarity check vs existing entries. cos > 0.7 = auto-merge, cos < 0.3 = auto-add, 0.3-0.7 = SimpleCall judgment. This saves ~80% of LLM calls on writes.

Index

Constants

View Source 
const (
	// MergeThreshold is the cosine similarity threshold above which entries
	// are considered duplicates and auto-merged.
	MergeThreshold float32 = 0.7

	// AddThreshold is the cosine similarity below which entries are
	// considered distinct and auto-added without LLM judgment.
	AddThreshold float32 = 0.3
)

MergeThresholds for merge-on-write classification.

Variables

This section is empty.

Functions

func FormatBufferLine 

func FormatBufferLine(role, message string) string

FormatBufferLine creates a timestamped buffer line. Format: "HH:MM role message"

func ScanContent 

func ScanContent(content string) error

ScanContent checks memory content for security threats. Returns an error if the content contains patterns that could compromise the agent.

Checks:

  • Invisible Unicode characters (zero-width spaces, direction overrides, BOM)
  • Prompt injection markers ("ignore previous instructions", etc.)
  • Credential exfiltration patterns (API keys, private keys, bearer tokens)

Types

type Buffer 

type Buffer struct {
	// contains filtered or unexported fields
}

Buffer is a simple ring buffer for session-level turn summaries. Thread-safe only if accessed from a single goroutine (the loop engine owns the buffer and serializes all access).

func NewBuffer 

func NewBuffer(cap int) *Buffer

NewBuffer creates a ring buffer with the given capacity. cap=0 means disabled (all appends are silently discarded).

func (*Buffer) Append 

func (b *Buffer) Append(line string)

Append adds a line to the buffer. If the buffer is at capacity, the oldest line is evicted first.

func (*Buffer) Cap 

func (b *Buffer) Cap() int

Cap returns the maximum number of lines.

func (*Buffer) Clear 

func (b *Buffer) Clear()

Clear removes all lines from the buffer.

func (*Buffer) Len 

func (b *Buffer) Len() int

Len returns the current number of lines.

func (*Buffer) Lines 

func (b *Buffer) Lines() []string

Lines returns a copy of the current buffer contents (oldest first).

type EpisodeMeta 

type EpisodeMeta struct {
	SessionID string    `json:"session_id"`
	Turns     int       `json:"turns"`
	CreatedAt time.Time `json:"created_at"`
	Summary   string    `json:"summary"` // truncated for index listing
}

EpisodeMeta holds metadata for a single episode.

type EpisodeStore 

type EpisodeStore struct {
	// contains filtered or unexported fields
}

EpisodeStore manages on-disk episode summaries (Tier 3 memory). Written after sessions with sufficient turns, searchable via SimpleCall.

func NewEpisodeStore 

func NewEpisodeStore(dir string, rankFn RankStrategy) *EpisodeStore

NewEpisodeStore creates an EpisodeStore rooted at dir. If rankFn is nil, a default ranker is used (SimpleCall-based — requires LLM client).

func (*EpisodeStore) Read 

func (e *EpisodeStore) Read(sessionID string) (string, error)

Read returns the full summary content for a session.

func (*EpisodeStore) ReadIndex 

func (e *EpisodeStore) ReadIndex() ([]EpisodeMeta, error)

ReadIndex reads the episode index from disk. Returns empty slice if the index file doesn't exist yet. Entries are ordered newest-first.

func (*EpisodeStore) Search 

func (e *EpisodeStore) Search(query string, limit int) ([]EpisodeMeta, error)

Search returns the most relevant episodes for a query, ranked by the configured RankStrategy. Limited to limit results.

func (*EpisodeStore) Write 

func (e *EpisodeStore) Write(sessionID, summary string, turns int) error

Write stores an episode summary for a session. Creates the episodes directory and updates the index.

func (*EpisodeStore) WriteIfEnough 

func (e *EpisodeStore) WriteIfEnough(sessionID, summary string, turns int) error

WriteIfEnough calls Write only if turns >= extractThreshold (3). Returns nil without writing if the threshold isn't met.

type FactStore 

type FactStore struct {
	// contains filtered or unexported fields
}

FactStore manages typed fact files (user.md and env.md) with character caps, duplicate prevention, and entry-level CRUD via substring matching.

func NewFactStore 

func NewFactStore(dir string, capUser, capEnv int) *FactStore

NewFactStore creates a FactStore rooted at dir. Fact files are stored as dir/user.md and dir/env.md. Caps limit total file size.

func (*FactStore) Add 

func (f *FactStore) Add(target, content string) error

Add appends a new entry to a fact file. Returns error if:

  • target is invalid
  • content is empty
  • content already exists (dedup)
  • adding would exceed the character cap

func (*FactStore) Entries 

func (f *FactStore) Entries(target string) ([]string, error)

Entries returns the individual entries as a string slice.

func (*FactStore) Read 

func (f *FactStore) Read(target string) (string, error)

Read returns the full content of a fact file. Returns empty string if the file doesn't exist yet.

func (*FactStore) Remove 

func (f *FactStore) Remove(target, oldText string) error

Remove finds an entry by substring match and removes it. Returns error if the substring doesn't match exactly one entry.

func (*FactStore) Replace 

func (f *FactStore) Replace(target, oldText, content string) error

Replace finds an entry by substring match and replaces it with new content. Returns error if the substring doesn't match exactly one entry.

type LLMClient 

type LLMClient interface {
	SimpleCall(ctx context.Context, system, user string) (string, error)
}

LLMClient abstracts the LLM calls needed by the memory system (SimpleCall for consolidation, episode extraction, and search).

type MemoryConfig 

type MemoryConfig struct {
	Enabled        bool    `json:"enabled"`
	FactsLimitUser int     `json:"facts_limit_user"`
	FactsLimitEnv  int     `json:"facts_limit_env"`
	BufferLines    int     `json:"buffer_lines"`
	BufferEnabled  bool    `json:"buffer_enabled"`
	MergeOnWrite   bool    `json:"merge_on_write"`
	ExtractOnEnd   bool    `json:"extract_on_end"`
	LLMSearch      bool    `json:"llm_search"`
	LLMExtract     bool    `json:"llm_extract"`
	LLMConsolidate bool    `json:"llm_consolidate"`
	MergeThreshold float32 `json:"merge_threshold"`
	AddThreshold   float32 `json:"add_threshold"`
}

MemoryConfig holds configuration for the memory system. Mirrors the JSON config section.

func DefaultMemoryConfig 

func DefaultMemoryConfig() MemoryConfig

DefaultMemoryConfig returns sensible defaults.

type MemoryManager 

type MemoryManager struct {
	// contains filtered or unexported fields
}

MemoryManager orchestrates all three tiers of memory: Facts (durable, in system prompt), Buffer (session-level context), and Episodes (on-disk extracted summaries with search).

func NewMemoryManager 

func NewMemoryManager(memoryDir string, llc LLMClient, cfg MemoryConfig) *MemoryManager

NewMemoryManager creates a fully wired MemoryManager. If llc is nil, LLM-dependent features (consolidation, episode search) degrade gracefully (no LLM call, fallback behavior).

func (*MemoryManager) AddFact 

func (m *MemoryManager) AddFact(target, content string) error

AddFact appends a new fact entry. Performs:

  1. Security scan (reject if dangerous)
  2. Dedup (FactStore handles this)
  3. Merge-on-write using go-vector RP if MergeOnWrite is enabled
  4. Fits the merge detector after mutation

func (*MemoryManager) AppendBuffer 

func (m *MemoryManager) AppendBuffer(role, message string)

AppendBuffer adds a turn summary to the in-memory ring buffer.

func (*MemoryManager) BuildSystemPrompt 

func (m *MemoryManager) BuildSystemPrompt() string

BuildSystemPrompt returns the memory section to inject into the system prompt. Returns empty string if memory is disabled or nothing to show.

func (*MemoryManager) ClearBuffer 

func (m *MemoryManager) ClearBuffer()

ClearBuffer resets the buffer for a new session.

func (*MemoryManager) Consolidate 

func (m *MemoryManager) Consolidate(target string) error

Consolidate uses the LLM to merge related entries in a target file for better density. Falls back to no-op if LLM is unavailable or LLMConsolidate is disabled in config.

func (*MemoryManager) GetBuffer 

func (m *MemoryManager) GetBuffer() []string

GetBuffer returns the current buffer lines (for system prompt injection).

func (*MemoryManager) OnSessionEnd 

func (m *MemoryManager) OnSessionEnd(sessionID string, turns int, messages []string)

OnSessionEnd is called when a session ends. If turns >= threshold, extracts durable facts using the LLM and stores them as an episode.

func (*MemoryManager) ReadFacts 

func (m *MemoryManager) ReadFacts() (userContent, envContent string, err error)

ReadFacts returns the full content of user and env fact files.

func (*MemoryManager) RemoveFact 

func (m *MemoryManager) RemoveFact(target, oldText string) error

RemoveFact removes a fact entry by substring.

func (*MemoryManager) ReplaceFact 

func (m *MemoryManager) ReplaceFact(target, oldText, content string) error

ReplaceFact replaces an existing fact entry.

func (*MemoryManager) RestoreBuffer 

func (m *MemoryManager) RestoreBuffer(lines []string)

RestoreBuffer loads buffer lines from a saved slice (e.g., from session).

func (*MemoryManager) SearchEpisodes 

func (m *MemoryManager) SearchEpisodes(query string, limit int) ([]EpisodeMeta, error)

SearchEpisodes returns the most relevant episodes for a query.

type MemoryTool 

type MemoryTool struct {
	// contains filtered or unexported fields
}

MemoryTool wraps a MemoryManager as a kode-compatible Tool.

func NewMemoryTool 

func NewMemoryTool(mm *MemoryManager) *MemoryTool

NewMemoryTool creates a tool that exposes memory CRUD + search to the agent.

func (*MemoryTool) Call 

func (t *MemoryTool) Call(args string) (string, error)

func (*MemoryTool) Description 

func (t *MemoryTool) Description() string

func (*MemoryTool) Name 

func (t *MemoryTool) Name() string

func (*MemoryTool) Schema 

func (t *MemoryTool) Schema() any

type MergeDetector 

type MergeDetector struct {
	// contains filtered or unexported fields
}

MergeDetector uses RandomProjections to quickly estimate whether a new fact entry overlaps with existing entries. This avoids ~80% of LLM calls during merge-on-write.

Lifecycle:

  1. NewMergeDetector(dims) — creates RP embedder
  2. Fit(corpus) — builds vocabulary from existing entries
  3. Classify(entry) → action + similarIdx + similarity
  4. After facts change → Fit(newCorpus) to rebuild vocabulary

Thresholds control the classification:

  • mergeThreshold: cosine above this → auto-merge (default 0.7)
  • addThreshold: cosine below this → auto-add (default 0.3)
  • Between thresholds: "judge" — requires LLM to decide

func NewMergeDetector 

func NewMergeDetector(dims int) *MergeDetector

NewMergeDetector creates a MergeDetector with the given output dimensionality for the RP embedder. Pass 0 for default (256). Uses default thresholds (0.7 merge, 0.3 add).

func NewMergeDetectorWithThresholds 

func NewMergeDetectorWithThresholds(dims int, mergeThreshold, addThreshold float32) *MergeDetector

NewMergeDetectorWithThresholds creates a MergeDetector with custom thresholds.

func (*MergeDetector) Classify 

func (m *MergeDetector) Classify(entry string) (action string, similarIdx int, similarity float32)

Classify returns the merge decision for a new entry vs the fitted corpus.

Returns:

  • action: "merge" | "add" | "judge" | "nobody"
  • similarIdx: index of the most similar corpus entry (for merge/judge)
  • similarity: cosine similarity [0, 1]

"nobody" means the corpus is empty — there's nothing to compare against.

func (*MergeDetector) Corpus 

func (m *MergeDetector) Corpus() []string

Corpus returns the current corpus (for inspection).

func (*MergeDetector) Fit 

func (m *MergeDetector) Fit(corpus []string)

Fit builds the RP vocabulary and pre-computes embeddings for all corpus entries. Call whenever facts change (after add/replace/remove).

type RankStrategy 

type RankStrategy func(query string, episodes []EpisodeMeta) ([]EpisodeMeta, error)

RankStrategy is an injectable function for ranking episodes by relevance to a query. The default implementation uses SimpleCall; tests can inject a deterministic mock.

func NewLLMRanker 

func NewLLMRanker(llm LLMClient) RankStrategy

NewLLMRanker creates a RankStrategy that uses an LLM client to rank episodes by semantic relevance to the query. Falls back to recency ordering if the LLM call fails or returns unparseable output.

Source Files

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