Cognitive Types

In addition to its memory type (decision, insight, learning, etc.), every memory is classified by its cognitive type. This mirrors how the human brain processes different kinds of information using different neural systems.

The Three Cognitive Types

Episodic Memories

Episodic memories are tied to specific events. They remember what happened, when, and where. They start with higher initial strength (+0.10 modifier) because events feel vivid when fresh, but they decay faster — the details fade over time while the lessons persist.

Examples:

• "The deploy failed Tuesday at 3pm because the migration script had a typo in the column name"
• "During the sprint retro, the team agreed that code reviews need a 24-hour SLA"
• "The client demo on March 12th crashed because we forgot to seed the staging database"

Characteristics:

• Rich in contextual details (time, place, people involved)
• Naturally time-anchored — they answer "what happened?"
• Higher initial impact but details become fuzzy over time
• Prime candidates for crystallization during sleep

Semantic Memories

Semantic memories represent abstracted knowledge — facts, rules, and principles that are not tied to a specific event. They use the default decay rate, making them stable long-term storage.

Examples:

• "React hooks must follow the rules of hooks — no conditional calls, no loops"
• "PostgreSQL JSONB indexes require a GIN index for efficient queries"
• "The billing system uses event sourcing with a 30-day compaction window"

Characteristics:

• Context-independent — true regardless of when or where you learned it
• Generalizable and reusable across projects
• Standard decay rate — stable over time
• Often the result of crystallizing multiple episodic memories

Procedural Memories

Procedural memories encode skills and workflows — the how-to knowledge that becomes automatic with practice. They start with lower strength (-0.10 modifier) because skills take time to establish, but once reinforced through recall, they decay extremely slowly.

Examples:

• "Steps to debug a memory leak: 1. Take a heap snapshot, 2. Identify retained objects, 3. Trace the retention chain, 4. Fix the reference"
• "Deployment checklist: Run tests, bump version, update changelog, create tag, push, verify staging, promote to production"
• "Git rebase workflow: fetch upstream, rebase onto main, resolve conflicts file-by-file, force push to branch"

Characteristics:

• Sequential or workflow-oriented — describes a process
• Low initial strength but extremely persistent once established
• Gets stronger through practice (repeated recall)
• Rarely needs updating — procedures tend to be stable

How Cognitive Types Affect Strength

The base strength of a memory is determined by its memory type, then modified by its cognitive type:

final_strength = base_strength + cognitive_modifier

For example:

• A decision (base 0.85) stored as episodic = 0.95 initial strength
• A decision (base 0.85) stored as semantic = 0.85 initial strength (no modifier)
• A decision (base 0.85) stored as procedural = 0.75 initial strength

The higher initial strength of episodic memories compensates for their faster decay — they start vivid and gradually lose detail, mirroring how human event memories work.

Crystallization

One of the most powerful features of Brain Memory is semantic crystallization, which happens during the sleep cycle.

When the agent notices frequently-recalled episodic memories, it extracts the generalizable principle into a new semantic memory. The event-specific details begin fading, but the lesson persists as stable long-term knowledge.

Example of crystallization:

Three episodic memories about deploy failures:

1. "Deploy failed March 5 due to missing env variable"
2. "Deploy failed March 19 because staging wasn't tested"
3. "Deploy failed April 2 due to migration script error"

Crystallize into one semantic memory:

• "Deploy failures consistently stem from skipping the pre-deploy checklist. The three critical gates are: env variable verification, staging validation, and migration script review."

The original episodic memories continue to decay (and may eventually be archived), but the crystallized semantic memory lives on with standard decay and a strong base.

How Cognitive Types Are Assigned

When you run /brain:memorize, the agent determines the cognitive type by analyzing the content:

• Episodic — Contains specific dates, events, people, "what happened" narratives
• Semantic — Expresses general rules, facts, principles, or abstracted knowledge
• Procedural — Describes step-by-step processes, workflows, or how-to instructions

The agent can also recognize transitions. If you discuss a specific event but then extract a general rule from it, the agent may create both an episodic memory (the event) and a semantic memory (the rule), with an association link between them.