> ## Documentation Index
> Fetch the complete documentation index at: https://qitor.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Context and memory contracts

> QitOS public API: context

Register contributors, selectors, budget policies and compactors with explicit extension names. Context selection does not grant tool authority. CompactionReceipt declares the input, output identity and losses; omission is not a lossless summary. Memory input is not a checkpoint store. Missing factories fail at composition. See the executable tutorial for method arguments and an observed lossy compaction.

[完整可运行教程 / Complete tutorial](/guides/memory-and-history) · [API index](/reference/api)

Signatures and fields below are extracted from the pinned source. Signatures are reference material, not standalone programs. Source links bind the same runtime baseline. Any does not imply arbitrary objects are supported; use the behavioral contract above and the linked tutorial.

The concrete module APIs are `qitos.kit.memory.adapter.MemorySourceAdapter(memory, *, namespace, query=None, required=False, priority=0)` and `qitos.kit.context.compaction.ClosedExchangeWindowCompactor()`. Bind them using the existing `extensions` mapping; no root export or Engine constructor option is added. Memdir restore is explicit about missing resources (`create=True` initializes); Markdown recall is instance-scoped. Required contributions take precedence over optional priorities.

RequestView now requires an explicit compaction policy for budget-driven exchange omission. Its `compact` callback receives eligible omitted IDs and the SHA-256 digest of the selected exchange projection, and must return a matching loss receipt. Preexisting receipts alone do not authorize new omission. The request builder owns the recent window and all protection checks; continuation protection is conservative. See the tutorial for the Python-only context budget/loss settings and migration boundaries.

<span id="qitos-core-context-staticcontextcontributor" />

## StaticContextContributor

```python theme={null}
from qitos.core.context import StaticContextContributor
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/context.py#L302)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
contributor = StaticContextContributor("notes.project", "project", "Use supplied notes only.")
```

```text theme={null}
Small reusable contributor for project/user/session context.
```

| Field                 | Type   | Default             |
| --------------------- | ------ | ------------------- |
| `contributor_id`      | `str`  | `required`          |
| `source`              | `str`  | `required`          |
| `value`               | `Any`  | `field(repr=False)` |
| `priority`            | `int`  | `0`                 |
| `requested_placement` | `str`  | `'developer'`       |
| `required`            | `bool` | `False`             |
| `persistence_horizon` | `str`  | `'request'`         |
| `sensitivity`         | `str`  | `'internal'`        |

<span id="qitos-core-context-prioritycontextselectionpolicy" />

## PriorityContextSelectionPolicy

```python theme={null}
from qitos.core.context import PriorityContextSelectionPolicy
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/context.py#L118)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
class AuditedSelector(PriorityContextSelectionPolicy):
    def select(self, contributions, **options):
        contributions = tuple(contributions)
        print([item.contribution_id for item in contributions])
        return super().select(contributions, **options)
```

```text theme={null}
Default deterministic priority/identity selection policy.
```

| Field       | Type  | Default                       |
| ----------- | ----- | ----------------------------- |
| `policy_id` | `str` | `'qitos.context.priority/v1'` |

<span id="qitos-core-context-prioritycontextselectionpolicy-select" />

### PriorityContextSelectionPolicy.select

```text theme={null}
select(contributions: Iterable[ContextContribution], *, budget: ContextBudget, already_used_units: int=0, counter: UnitCounter=default_unit_counter) -> ContextSelection
```

| Parameter            | Type                            | Default                |
| -------------------- | ------------------------------- | ---------------------- |
| `contributions`      | `Iterable[ContextContribution]` | `required`             |
| `budget`             | `ContextBudget`                 | `required`             |
| `already_used_units` | `int`                           | `0`                    |
| `counter`            | `UnitCounter`                   | `default_unit_counter` |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/context.py#L123)

<span id="qitos-core-context-declaredcontextbudgetpolicy" />

## DeclaredContextBudgetPolicy

```python theme={null}
from qitos.core.context import DeclaredContextBudgetPolicy
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/context.py#L189)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
policy = DeclaredContextBudgetPolicy(default_max_input_units=4096)
```

```text theme={null}
Use adapter-declared capacity; never infer it from a model name.
```

| Field                        | Type  | Default                              |
| ---------------------------- | ----- | ------------------------------------ |
| `default_max_input_units`    | `int` | `120000`                             |
| `unit`                       | `str` | `'characters'`                       |
| `protected_recent_exchanges` | `int` | `1`                                  |
| `policy_id`                  | `str` | `'qitos.context.declared_budget/v1'` |

<span id="qitos-core-request_view-compactionreceipt" />

## CompactionReceipt

```python theme={null}
from qitos.core.request_view import CompactionReceipt
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/request_view.py#L530)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
# receipt is returned by the compactor in the context tutorial.
print(receipt.declared_losses, receipt.output_digest)
```

| Field                | Type              | Default    |
| -------------------- | ----------------- | ---------- |
| `receipt_id`         | `str`             | `required` |
| `input_exchange_ids` | `tuple[str, ...]` | `required` |
| `output_digest`      | `str`             | `required` |
| `policy_id`          | `str`             | `required` |
| `declared_losses`    | `tuple[str, ...]` | `()`       |
| `model_reference`    | `Optional[str]`   | `None`     |

<span id="qitos-core-memory-memoryrecord" />

## MemoryRecord

```python theme={null}
from qitos.core.memory import MemoryRecord
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/memory.py#L20)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
record = MemoryRecord("user", "remembered-value=17", 0)
```

```text theme={null}
One logical memory fact; independent equal facts receive distinct IDs.
```

| Field       | Type             | Default                                      |
| ----------- | ---------------- | -------------------------------------------- |
| `role`      | `str`            | `required`                                   |
| `content`   | `Any`            | `required`                                   |
| `step_id`   | `int`            | `required`                                   |
| `metadata`  | `Dict[str, Any]` | `field(default_factory=dict)`                |
| `record_id` | `str`            | `field(default_factory=lambda: uuid4().hex)` |

<span id="qitos-core-memory-memoryresourceerror" />

## MemoryResourceError

```python theme={null}
from qitos.core.memory import MemoryResourceError
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/memory.py#L13)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
# Restore raises MemoryResourceError if the bound root is missing.
```

```text theme={null}
A bound durable memory resource is missing or unavailable.
```

<span id="qitos-kit-memory-memdir_memory-memdirmemory" />

## MemdirMemory

```python theme={null}
from qitos.kit.memory.memdir_memory import MemdirMemory
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L16)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
memory = MemdirMemory("./project-memory", create=True)
memory.append(MemoryRecord("user", "remembered-value=17", 0))
# Later process: MemdirMemory("./project-memory")
```

```text theme={null}
Persist text records with stable identity and fresh disk retrieval.

Restore is the default and fails if a bound root is missing. Pass
``create=True`` only to explicitly initialize a namespace. ``reset`` and
``evict`` affect the append-time cache only; ``delete`` removes a local fact.
Arbitrary Python/JSON content and metadata are not a durable round-trip API.
```

```text theme={null}
MemdirMemory(memory_dir: str='.qitos/memory', *, global_memory_dir: str | None=None, create: bool=False, max_index_entries: int=200, max_index_chars: int=25000) -> Any (see behavior contract)
```

| Parameter           | Type          | Default           |
| ------------------- | ------------- | ----------------- |
| `memory_dir`        | `str`         | `'.qitos/memory'` |
| `global_memory_dir` | `str \| None` | `None`            |
| `create`            | `bool`        | `False`           |
| `max_index_entries` | `int`         | `200`             |
| `max_index_chars`   | `int`         | `25000`           |

<span id="qitos-kit-memory-memdir_memory-memdirmemory-append" />

### MemdirMemory.append

```text theme={null}
append(record: MemoryRecord) -> None
```

| Parameter | Type           | Default    |
| --------- | -------------- | ---------- |
| `record`  | `MemoryRecord` | `required` |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L47)

<span id="qitos-kit-memory-memdir_memory-memdirmemory-retrieve" />

### MemdirMemory.retrieve

```text theme={null}
retrieve(query: Optional[Dict[str, Any]]=None, state: Any=None, observation: Any=None) -> List[MemoryRecord]
```

| Parameter     | Type                       | Default |
| ------------- | -------------------------- | ------- |
| `query`       | `Optional[Dict[str, Any]]` | `None`  |
| `state`       | `Any`                      | `None`  |
| `observation` | `Any`                      | `None`  |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L103)

<span id="qitos-kit-memory-memdir_memory-memdirmemory-summarize" />

### MemdirMemory.summarize

```text theme={null}
summarize(max_items: int=30) -> str
```

| Parameter   | Type  | Default |
| ----------- | ----- | ------- |
| `max_items` | `int` | `30`    |

```text theme={null}
Render current records, never stale index snippets after external edits.
```

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L142)

<span id="qitos-kit-memory-memdir_memory-memdirmemory-reset" />

### MemdirMemory.reset

```text theme={null}
reset(run_id: Optional[str]=None) -> None
```

| Parameter | Type            | Default |
| --------- | --------------- | ------- |
| `run_id`  | `Optional[str]` | `None`  |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L157)

<span id="qitos-kit-memory-memdir_memory-memdirmemory-evict" />

### MemdirMemory.evict

```text theme={null}
evict() -> int
```

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L150)

<span id="qitos-kit-memory-memdir_memory-memdirmemory-delete" />

### MemdirMemory.delete

```text theme={null}
delete(record_id: str) -> bool
```

| Parameter   | Type  | Default    |
| ----------- | ----- | ---------- |
| `record_id` | `str` | `required` |

```text theme={null}
Forget one logical record in this namespace, never global memory.

Idempotent for an absent identity. This is local-file deletion, not
secure erasure or a concurrent multi-file transaction. Callers serialize
writes to one Memdir namespace; use a transactional backend otherwise.
```

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/memdir_memory.py#L78)

<span id="qitos-kit-memory-markdown_file_memory-markdownfilememory" />

## MarkdownFileMemory

```python theme={null}
from qitos.kit.memory.markdown_file_memory import MarkdownFileMemory
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/markdown_file_memory.py#L12)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
memory = MarkdownFileMemory("./run-memory.md")
# Existing logs are not reloaded; recall is instance-scoped.
```

```text theme={null}
Persist memory records in a local markdown log file.
```

```text theme={null}
MarkdownFileMemory(path: str='memory.md', max_in_memory: int=200) -> Any (see behavior contract)
```

| Parameter       | Type  | Default       |
| --------------- | ----- | ------------- |
| `path`          | `str` | `'memory.md'` |
| `max_in_memory` | `int` | `200`         |

<span id="qitos-kit-memory-adapter-memorysourceadapter" />

## MemorySourceAdapter

```python theme={null}
from qitos.kit.memory.adapter import MemorySourceAdapter
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/adapter.py#L15)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
source = MemorySourceAdapter(memory, namespace="project", required=True)
# Bind source as extensions["project_memory"].
```

```text theme={null}
Recall a factory-bound namespace as user-level context data.

Namespace is a logical label, not a directory selector or an authorization.
The factory must bind the correct Memory resource. No global memory is read
by this adapter. Every request recalls fresh data, including after restore;
revision is provenance, never a permanent suppression cache.
```

```text theme={null}
MemorySourceAdapter(memory: Memory, *, namespace: str, query: Mapping[str, Any] | None=None, required: bool=False, priority: int=0) -> None
```

| Parameter   | Type                        | Default    |
| ----------- | --------------------------- | ---------- |
| `memory`    | `Memory`                    | `required` |
| `namespace` | `str`                       | `required` |
| `query`     | `Mapping[str, Any] \| None` | `None`     |
| `required`  | `bool`                      | `False`    |
| `priority`  | `int`                       | `0`        |

<span id="qitos-kit-memory-adapter-memorysourceadapter-contribute" />

### MemorySourceAdapter.contribute

```text theme={null}
contribute(request: Any) -> Sequence[ContextContribution]
```

| Parameter | Type  | Default    |
| --------- | ----- | ---------- |
| `request` | `Any` | `required` |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/adapter.py#L48)

<span id="qitos-kit-memory-adapter-memorysourceadapter-reset" />

### MemorySourceAdapter.reset

```text theme={null}
reset(run_id: str | None=None) -> None
```

| Parameter | Type          | Default |
| --------- | ------------- | ------- |
| `run_id`  | `str \| None` | `None`  |

```text theme={null}
No owned state; never reset the borrowed memory.
```

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/adapter.py#L79)

<span id="qitos-kit-memory-adapter-memorysourceadapter-close" />

### MemorySourceAdapter.close

```text theme={null}
close() -> None
```

```text theme={null}
No owned resources; never close the borrowed memory.
```

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/memory/adapter.py#L82)

<span id="qitos-kit-context-compaction-closedexchangewindowcompactor" />

## ClosedExchangeWindowCompactor

```python theme={null}
from qitos.kit.context.compaction import ClosedExchangeWindowCompactor
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/context/compaction.py#L12)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
extensions["closed_window"] = ClosedExchangeWindowCompactor
# Configure compaction={"provider": "closed_window"}; the policy supplies receipts.
```

```text theme={null}
Omit the oldest eligible closed exchanges without a summary.

RequestView owns eligibility and the ContextBudget recent-window boundary.
This stateless policy authorizes that derived selection and records its loss;
it never modifies an ExchangeLog or widens a budget or codec loss setting.
```

<span id="qitos-kit-context-compaction-closedexchangewindowcompactor-compact" />

### ClosedExchangeWindowCompactor.compact

```text theme={null}
compact(*, exchange_ids: Sequence[str], selected_digest: str, required_units: int, available_units: int) -> CompactionReceipt | None
```

| Parameter         | Type            | Default    |
| ----------------- | --------------- | ---------- |
| `exchange_ids`    | `Sequence[str]` | `required` |
| `selected_digest` | `str`           | `required` |
| `required_units`  | `int`           | `required` |
| `available_units` | `int`           | `required` |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/kit/context/compaction.py#L22)

<span id="qitos-core-request_view-requestview" />

## RequestView

```python theme={null}
from qitos.core.request_view import RequestView
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/request_view.py#L794)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
# Advanced direct projection; normal users select the configured compactor.
view = RequestView.from_exchange_log(log, compaction_policy=ClosedExchangeWindowCompactor())
```

```text theme={null}
One immutable, deterministic provider-neutral model request view.
```

| Field                     | Type                            | Default                                                                                                 |
| ------------------------- | ------------------------------- | ------------------------------------------------------------------------------------------------------- |
| `request_id`              | `str`                           | `required`                                                                                              |
| `target`                  | `RequestTarget`                 | `required`                                                                                              |
| `source_log_id`           | `str`                           | `required`                                                                                              |
| `source_log_digest`       | `str`                           | `required`                                                                                              |
| `selected_items_json`     | `tuple[str, ...]`               | `field(repr=False)`                                                                                     |
| `instructions_json`       | `tuple[str, ...]`               | `field(default=(), repr=False)`                                                                         |
| `tool_schemas_json`       | `tuple[str, ...]`               | `field(default=(), repr=False)`                                                                         |
| `context_json`            | `tuple[str, ...]`               | `field(default=(), repr=False)`                                                                         |
| `capability_requirements` | `tuple[str, ...]`               | `()`                                                                                                    |
| `reasoning_policy`        | `ReasoningPolicy`               | `field(default_factory=ReasoningPolicy)`                                                                |
| `continuation`            | `Optional[ContinuationRef]`     | `None`                                                                                                  |
| `context_budget`          | `ContextBudget`                 | `field(default_factory=ContextBudget)`                                                                  |
| `selection`               | `SelectionReport`               | `field(default_factory=lambda: SelectionReport((), (), (), (), (), (), (), (), 0, 0, 0, 'characters'))` |
| `compaction_receipts`     | `tuple[CompactionReceipt, ...]` | `()`                                                                                                    |
| `artifact_refs`           | `tuple[ArtifactRef, ...]`       | `()`                                                                                                    |
| `steering_boundary_json`  | `str`                           | `'{}'`                                                                                                  |
| `correlation_facts_json`  | `tuple[str, ...]`               | `field(default=(), repr=False)`                                                                         |
| `provenance_json`         | `str`                           | `'{}'`                                                                                                  |
| `protocol_id`             | `str`                           | `'unknown'`                                                                                             |
| `tool_use_policy`         | `str`                           | `'auto'`                                                                                                |
| `tool_use_satisfied`      | `bool`                          | `False`                                                                                                 |
| `schema_version`          | `str`                           | `REQUEST_VIEW_SCHEMA_VERSION`                                                                           |

<span id="qitos-core-request_view-requestview-from-exchange-log" />

### RequestView\.from\_exchange\_log

```text theme={null}
from_exchange_log(log: ExchangeLog, *, model: Any=None, target: Optional[RequestTarget]=None, instructions: Iterable[Mapping[str, Any]]=(), tool_schemas: Iterable[Mapping[str, Any]]=(), capability_requirements: Iterable[str]=(), reasoning_policy: Optional[ReasoningPolicy]=None, continuation: Optional[ContinuationRef]=None, context_budget: Optional[ContextBudget]=None, context_contributions: Iterable[ContextContribution]=(), context_selection_policy: Any=None, context_unit_counter: Any=None, compaction_receipts: Iterable[CompactionReceipt]=(), compaction_policy: Any=None, artifact_refs: Iterable[ArtifactRef]=(), available_artifact_ids: Optional[Iterable[str]]=None, protocol_id: str='unknown', tool_use_policy: str='auto', tool_use_satisfied: bool=False) -> 'RequestView'
```

| Parameter                  | Type                            | Default     |
| -------------------------- | ------------------------------- | ----------- |
| `log`                      | `ExchangeLog`                   | `required`  |
| `model`                    | `Any`                           | `None`      |
| `target`                   | `Optional[RequestTarget]`       | `None`      |
| `instructions`             | `Iterable[Mapping[str, Any]]`   | `()`        |
| `tool_schemas`             | `Iterable[Mapping[str, Any]]`   | `()`        |
| `capability_requirements`  | `Iterable[str]`                 | `()`        |
| `reasoning_policy`         | `Optional[ReasoningPolicy]`     | `None`      |
| `continuation`             | `Optional[ContinuationRef]`     | `None`      |
| `context_budget`           | `Optional[ContextBudget]`       | `None`      |
| `context_contributions`    | `Iterable[ContextContribution]` | `()`        |
| `context_selection_policy` | `Any`                           | `None`      |
| `context_unit_counter`     | `Any`                           | `None`      |
| `compaction_receipts`      | `Iterable[CompactionReceipt]`   | `()`        |
| `compaction_policy`        | `Any`                           | `None`      |
| `artifact_refs`            | `Iterable[ArtifactRef]`         | `()`        |
| `available_artifact_ids`   | `Optional[Iterable[str]]`       | `None`      |
| `protocol_id`              | `str`                           | `'unknown'` |
| `tool_use_policy`          | `str`                           | `'auto'`    |
| `tool_use_satisfied`       | `bool`                          | `False`     |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/request_view.py#L1017)

<span id="qitos-core-request_view-contextbudgetexceedederror" />

## ContextBudgetExceededError

```python theme={null}
from qitos.core.request_view import ContextBudgetExceededError
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/core/request_view.py#L60)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
# Required/protected exchanges cannot be removed to make a request fit.
```

<span id="qitos-engine-runtime-lifecyclepolicy" />

## LifecyclePolicy

```python theme={null}
from qitos.engine.runtime import LifecyclePolicy
```

[Source @ d000a42](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/engine/runtime.py#L88)

[Usage and executable example](/guides/memory-and-history)

Usage fragment: continues with objects from the linked complete tutorial; not a standalone program.

```python theme={null}
class PauseFirstTool(LifecyclePolicy):
    policy_id = "notes.pause"
    def should_pause(self, context):
        return context.step_id == 0
```

```text theme={null}
Replaceable cooperative lifecycle policy; never a worker scheduler.
```

<span id="qitos-engine-runtime-lifecyclepolicy-should-pause" />

### LifecyclePolicy.should\_pause

```text theme={null}
should_pause(context: RuntimeSnapshotContext) -> bool
```

| Parameter | Type                     | Default    |
| --------- | ------------------------ | ---------- |
| `context` | `RuntimeSnapshotContext` | `required` |

[Source](https://github.com/WhitzardAgent/WhitzardOS/blob/d000a42aff30b87c812850ac1019ca197f420c09/qitos/engine/runtime.py#L94)