Tool Framework Specification

Document ID: AGENT-002
File Path: docs/04-agent-framework/tool-framework.md
Version: 1.0.0
Status: Draft
Owner: AI Platform Team
Last Updated: 2026-06-26

1. Purpose

The Tool Framework is one of the core subsystems of the Wovyr AI Platform.

It enables AI agents to safely interact with external systems through a standardized, secure, observable, and extensible tool execution framework.

Unlike traditional AI applications where tools are directly embedded inside prompts, Wovyr treats tools as first-class runtime components.

Every tool:

is registered
versioned
permission-controlled
sandboxed
observable
independently deployable

The framework allows thousands of tools to coexist across multiple tenants and execution environments.

2. Objectives

The Tool Framework must provide:

Pluggable tools
Runtime discovery
Dynamic registration
Secure execution
Fine-grained permissions
Tool versioning
Distributed execution
Retry support
Timeout handling
Streaming responses
Event publishing
Metrics
Auditing

3. Scope

The Tool Framework is responsible for:

Tool registration
Tool discovery
Permission validation
Parameter validation
Tool execution
Result validation
Error handling
Metrics
Auditing
Tool sandboxing

The framework is not responsible for:

LLM execution
Workflow scheduling
Agent planning
Memory retrieval

4. Design Principles

The Tool Framework follows these principles:

Every tool is isolated.
Every tool is versioned.
Every execution is auditable.
Tools never directly access runtime memory.
Tools are stateless.
Tool outputs are deterministic whenever possible.
Permissions are evaluated before execution.
Every invocation generates events.

5. High-Level Architecture

                      Agent Runtime
                           │
                           ▼
                   Tool Execution Engine
                           │
      ┌────────────────────┼────────────────────┐
      ▼                    ▼                    ▼
 Tool Registry      Permission Engine     Validator
      │                    │                    │
      └────────────────────┼────────────────────┘
                           ▼
                     Tool Dispatcher
                           │
      ┌────────────────────┼────────────────────┐
      ▼                    ▼                    ▼
 Built-in Tools     Custom Tools        Remote Tools
                           │
                           ▼
                     External Systems

6. Core Components

Component	Responsibility
Tool Registry	Stores tool metadata
Dispatcher	Routes execution
Validator	Validates inputs and outputs
Permission Engine	Authorization
Sandbox Manager	Execution isolation
Runtime Adapter	Executes tools
Metrics Collector	Monitoring
Audit Logger	Audit events
Retry Handler	Retry failed tools
Timeout Manager	Enforce execution limits

7. Tool Categories

The framework supports multiple categories.

System Tools

Examples:

File System
Shell
Process
Environment
Clipboard

Development Tools

Examples:

Rust Compiler
Cargo
Docker
Git
Kubernetes
Terraform

Data Tools

Examples:

PostgreSQL
MySQL
MongoDB
Redis
Elasticsearch
ClickHouse

AI Tools

Examples:

Embeddings
Vector Search
OCR
Image Generation
Speech Recognition
Text-to-Speech

Communication Tools

Examples:

Email
Slack
Discord
Microsoft Teams
SMS
Push Notifications

Cloud Tools

Examples:

AWS
Azure
Google Cloud
DigitalOcean
Cloudflare

Blockchain Tools

Examples:

Ethereum
Solana
Bitcoin
Hyperledger
StarkNet
Polygon

Business Tools

Examples:

Salesforce
SAP
Stripe
Shopify
Jira
ServiceNow

8. Tool Lifecycle

Created

↓

Validated

↓

Registered

↓

Enabled

↓

Invoked

↓

Completed

↓

Deprecated

↓

Archived

Tool definitions are immutable once published.

9. Tool Registration

Registration workflow:

Developer

↓

Tool Manifest

↓

Schema Validation

↓

Permission Validation

↓

Registry

↓

Published

Tools may be registered dynamically without restarting the platform.

10. Tool Manifest

Every tool contains metadata.

Example:

apiVersion: wovyr.ai/v1

kind: Tool

metadata:

  id: postgres-query

  version: 1.0.0

  category: database

  owner: database-team

spec:

  runtime: rust

  timeout: 30s

  retry:

    attempts: 3

  permissions:

    - database.read

    - database.query

11. Tool Metadata

Required fields:

Field	Description
id	Unique identifier
version	Semantic version
category	Tool category
owner	Owning team
description	Human-readable description
runtime	Execution runtime
timeout	Default timeout
permissions	Required permissions

12. Tool Registry

The Tool Registry stores:

Tool metadata
Versions
Input schemas
Output schemas
Permission requirements
Runtime information
Health status
Deprecation status

The registry acts as the authoritative catalog for all tools.

13. Registry Architecture

                  Tool Registry
                       │
        ┌──────────────┼──────────────┐
        ▼              ▼              ▼
   Metadata      Input Schemas   Output Schemas
        │              │              │
        └──────────────┼──────────────┘
                       ▼
                  Version Store
                       │
                       ▼
                  Runtime Cache

14. Tool Discovery

Agents discover tools through the registry.

Supported discovery methods:

By ID
By Category
By Tags
By Capability
By Labels
By Version
By Owner

Example:

Agent

↓

Find Tool

↓

Registry Lookup

↓

Return Tool Metadata

15. Version Management

Each tool follows Semantic Versioning.

Example:

postgres-query

1.0.0

1.1.0

2.0.0

Multiple versions may exist simultaneously.

Agents specify the desired version or allow the runtime to select the latest compatible version.

16. Tool Capabilities

Each tool advertises capabilities.

Example:

capabilities:

  streaming: true

  async: true

  cancellation: true

  retries: true

  checkpointable: false

Capabilities are used by the Agent Runtime to optimize execution.

17. Tool Labels

Labels support filtering and policy enforcement.

Example:

labels:

  language: rust

  domain: blockchain

  risk: medium

  environment: production

18. Tool Health

Each tool exposes runtime health.

Possible states:

Healthy

↓

Degraded

↓

Unavailable

↓

Maintenance

The registry periodically refreshes health status.

19. Tool Deprecation

Deprecation lifecycle:

Active

↓

Deprecated

↓

Read Only

↓

Archived

↓

Deleted

Deprecated tools remain available until their end-of-life date.

20. Tool Execution Overview

Execution flow:

Agent Request

↓

Lookup Tool

↓

Validate Permissions

↓

Validate Input

↓

Allocate Sandbox

↓

Execute Tool

↓

Validate Output

↓

Publish Event

↓

Return Result

Every execution is tracked by a unique execution ID.

End of Part 1

Next: Part 2 — Tool SDK, Input/Output Schemas, Permission Engine, Security Model, and Sandboxing.

21. Tool SDK

The Tool SDK is the primary interface for developing tools that integrate with the Wovyr AI Platform.

The SDK provides:

Strongly typed APIs
Tool registration
Schema generation
Context access
Authentication helpers
Secret resolution
Logging
Metrics
Error handling
Streaming support

SDKs will be provided for:

Rust (Primary)
TypeScript
Python
Go
Java
C#

Rust is the reference implementation.

22. Tool Execution Context

Every tool receives an immutable execution context.

Example:

executionId:
workflowId:
activityId:
agentId:
tenantId:
userId:
requestId:
correlationId:
traceId:
timestamp:
environment:
permissions:
variables:
metadata:

The context cannot be modified by the tool.

23. Tool Input Schema

Every tool defines a strict input schema.

Example:

input:

  type: object

  required:
    - sql

  properties:

    sql:
      type: string

    timeout:
      type: integer

    readonly:
      type: boolean

Input validation occurs before execution.

24. Tool Output Schema

Example:

output:

  type: object

  properties:

    rows:
      type: array

    rowCount:
      type: integer

    duration:
      type: integer

Outputs are validated before returning to the agent.

25. Tool Invocation Lifecycle

Invocation Requested

↓

Registry Lookup

↓

Permission Check

↓

Secret Resolution

↓

Input Validation

↓

Sandbox Allocation

↓

Execution

↓

Output Validation

↓

Audit Logging

↓

Metrics Collection

↓

Response Returned

26. Permission Engine

Every tool invocation passes through the Permission Engine.

Responsibilities:

Identity verification
Tenant validation
Role evaluation
Capability validation
Environment restrictions
Resource authorization

No tool executes without successful authorization.

27. Permission Model

Permissions are hierarchical.

Example:

filesystem

├── read

├── write

├── delete

└── execute

Example:

database

├── read

├── write

├── schema

└── admin

28. Policy Evaluation

Policy order:

Platform Policy

↓

Organization Policy

↓

Project Policy

↓

Agent Policy

↓

Tool Policy

↓

Execution Allowed

The most restrictive rule always wins.

29. Secret Management

Secrets are never embedded inside tool definitions.

Instead:

credentials:

  database:

    secretRef:

      production-postgres

The runtime resolves secrets during execution.

Supported secret providers:

HashiCorp Vault
AWS Secrets Manager
Azure Key Vault
Google Secret Manager
Kubernetes Secrets

30. Environment Variables

Approved environment variables may be injected.

Example:

environment:

  LOG_LEVEL: INFO

  CACHE_SIZE: 512

  TEMP_DIRECTORY: /tmp

Sensitive variables are masked from logs.

31. Sandboxing

Every tool executes inside an isolated environment.

Supported sandbox types:

Native Process
WASI
Docker
Firecracker MicroVM
Kubernetes Pod
gVisor
Remote Worker

The sandbox type is configurable per tool.

32. Sandbox Lifecycle

Allocate

↓

Initialize

↓

Inject Context

↓

Execute

↓

Collect Results

↓

Destroy

↓

Cleanup

Ephemeral sandboxes are preferred for untrusted tools.

33. Resource Limits

Each sandbox enforces limits.

Example:

limits:

  cpu: 2

  memory: 1Gi

  disk: 5Gi

  timeout: 30s

  network: restricted

Limits prevent resource exhaustion.

34. Network Policies

Tools declare required network access.

Example:

network:

  outbound:

    allow:

      - github.com

      - api.openai.com

  inbound:

    deny: all

Default policy:

Deny All

35. Filesystem Policies

Filesystem access is explicitly granted.

Example:

filesystem:

  allow:

    - /workspace

    - /tmp

  readonly:

    - /usr

    - /etc

Access outside approved paths is denied.

36. Process Isolation

Every execution receives:

Dedicated process
Dedicated PID namespace
Dedicated filesystem
Dedicated memory space

Process sharing is prohibited.

37. Timeouts

Timeout hierarchy:

Execution Timeout

↓

Grace Period

↓

Forced Termination

↓

Cleanup

Example:

timeout:

  execution: 60s

  grace: 5s

38. Cancellation

Cancellation sources:

User request
Workflow cancellation
Timeout
Scheduler preemption
Resource exhaustion

Cancelled tools must release all resources.

39. Error Handling

Standard error categories:

Error	Retry
ValidationError	No
PermissionDenied	No
Timeout	Yes
NetworkFailure	Yes
InternalError	Yes
ToolUnavailable	Yes
ConfigurationError	No

Errors are serialized into a standard response format.

40. Retry Integration

Retry policies may be declared.

Example:

retry:

  attempts: 5

  strategy: exponential

  initialDelay: 2s

  maxDelay: 2m

  jitter: true

Retries integrate with the Workflow Retry Engine.

End of Part 2

Next: Part 3 — Rust SDK, Tool Traits, Plugin System, Streaming Protocol, Events, Metrics, and Module Organization.

41. Rust Tool SDK

The Rust SDK is the reference implementation for developing Wovyr tools.

The SDK provides:

Strongly typed tool interfaces
Automatic schema generation
Async execution
Context injection
Secret resolution
Metrics integration
Structured logging
Streaming support
Error serialization

All official Wovyr tools are implemented using the Rust SDK.

42. Core Rust Traits

Every tool implements the Tool trait.

#[async_trait]
pub trait Tool: Send + Sync {
    fn metadata(&self) -> ToolMetadata;

    async fn execute(
        &self,
        ctx: ToolContext,
        request: ToolRequest,
    ) -> Result<ToolResponse, ToolError>;
}

The runtime invokes the execute() method after validation and authorization.

43. Tool Metadata

Every tool exposes immutable metadata.

Example:

pub struct ToolMetadata {
    pub id: String,
    pub version: String,
    pub category: String,
    pub description: String,
    pub author: String,
    pub permissions: Vec<String>,
    pub timeout: Duration,
}

Metadata is registered during tool initialization.

44. Tool Context

The runtime injects a ToolContext.

pub struct ToolContext {
    pub execution_id: ExecutionId,
    pub workflow_id: WorkflowId,
    pub activity_id: ActivityId,
    pub tenant_id: TenantId,
    pub trace_id: TraceId,
    pub secrets: SecretResolver,
    pub logger: Logger,
    pub metrics: MetricsCollector,
}

The context is immutable and thread-safe.

45. Tool Request

Requests are serialized before execution.

pub struct ToolRequest {
    pub parameters: serde_json::Value,
}

Parameter validation occurs before deserialization.

46. Tool Response

Every tool returns a standardized response.

pub struct ToolResponse {
    pub success: bool,
    pub payload: serde_json::Value,
    pub metadata: HashMap<String, String>,
}

Responses must conform to the declared output schema.

47. Tool Errors

All tools return standardized errors.

pub enum ToolError {

    Validation,

    PermissionDenied,

    Timeout,

    Internal,

    Network,

    Dependency,

    Cancelled,

    Retryable,

    Unknown,
}

Errors are serialized and published as events.

48. Plugin Architecture

The framework supports dynamically loadable plugins.

Tool Package

↓

Manifest

↓

Validation

↓

Registry

↓

Runtime Loader

↓

Execution

Plugins can be enabled or disabled without recompiling the platform.

49. Plugin Package Structure

postgres-query/

├── tool.yaml

├── Cargo.toml

├── README.md

├── LICENSE

├── src/

│   ├── lib.rs

│   ├── execute.rs

│   ├── schema.rs

│   ├── permissions.rs

│   └── errors.rs

└── tests/

Every package includes a manifest and implementation.

50. Streaming Tools

Some tools produce incremental output.

Supported streaming use cases:

AI responses
File downloads
Database exports
Video processing
Long-running computations

Streaming avoids buffering large payloads.

51. Streaming Protocol

Execution flow:

Execute

↓

Open Stream

↓

Chunk

↓

Chunk

↓

Chunk

↓

Complete

↓

Close Stream

Each chunk is independently acknowledged.

52. Event Integration

Every execution generates events.

Examples:

ToolRequested

↓

ToolValidated

↓

ToolStarted

↓

ToolProgress

↓

ToolCompleted

↓

ToolFailed

↓

ToolCancelled

Events are published to the Event Bus.

53. Audit Logging

Every execution generates immutable audit records.

Example:

executionId:
toolId:
toolVersion:
agentId:
workflowId:
tenantId:
status:
duration:
timestamp:

Audit logs are retained according to platform policy.

54. Metrics Collection

Metrics include:

Invocation count
Success rate
Failure rate
Timeout count
Retry count
Average latency
P95 latency
P99 latency
CPU usage
Memory usage

Metrics integrate with Prometheus-compatible collectors.

55. Tracing

Distributed tracing follows the complete execution path.

Workflow

↓

Agent

↓

Tool

↓

Database

↓

Response

Trace propagation uses OpenTelemetry context.

56. Health Monitoring

Every tool exposes health endpoints.

Health states:

Healthy

↓

Degraded

↓

Unavailable

Health information is periodically refreshed by the registry.

57. Tool Registry API

The registry exposes interfaces for runtime discovery.

pub trait ToolRegistry {

    fn register(
        &mut self,
        tool: Box<dyn Tool>,
    ) -> Result<()>;

    fn unregister(
        &mut self,
        id: &ToolId,
    ) -> Result<()>;

    fn get(
        &self,
        id: &ToolId,
    ) -> Option<&dyn Tool>;

    fn list(&self)
        -> Vec<ToolMetadata>;
}

58. Tool Dispatcher

The dispatcher selects the correct implementation.

Responsibilities:

Version resolution
Permission validation
Runtime selection
Sandbox allocation
Invocation
Response collection

59. Crate Organization

engine-tools/

├── sdk/
│   ├── tool.rs
│   ├── context.rs
│   ├── request.rs
│   ├── response.rs
│   ├── metadata.rs
│   ├── errors.rs
│   └── mod.rs
│
├── registry/
│   ├── registry.rs
│   ├── discovery.rs
│   ├── cache.rs
│   └── mod.rs
│
├── dispatcher/
│   ├── dispatcher.rs
│   ├── executor.rs
│   ├── validator.rs
│   └── mod.rs
│
├── sandbox/
│   ├── docker.rs
│   ├── firecracker.rs
│   ├── wasi.rs
│   ├── kubernetes.rs
│   └── mod.rs
│
├── permissions/
├── metrics/
├── events/
├── tracing/
├── plugins/
└── mod.rs

60. Example Tool

pub struct EchoTool;

#[async_trait]
impl Tool for EchoTool {

    fn metadata(&self) -> ToolMetadata {
        ToolMetadata::new(
            "echo",
            "1.0.0",
            "utility",
        )
    }

    async fn execute(
        &self,
        _ctx: ToolContext,
        req: ToolRequest,
    ) -> Result<ToolResponse, ToolError> {

        Ok(
            ToolResponse::success(
                req.parameters
            )
        )
    }
}

The Echo Tool demonstrates the minimal implementation required for a custom tool.

End of Part 3

Next: Part 4 — Performance, Testing Strategy, Non-Functional Requirements, Future Roadmap, Related Documents, and Revision History.

61. Tool Composition

Multiple tools may be composed into a single execution pipeline.

Example:

User Request
      │
      ▼
Filesystem Tool
      │
      ▼
Rust Compiler
      │
      ▼
Docker Builder
      │
      ▼
Git Tool
      │
      ▼
GitHub Tool
      │
      ▼
Response

Composition enables complex automation while keeping individual tools focused on a single responsibility.

62. Tool Chaining

The Agent Runtime supports dynamic tool chaining.

Example:

Planner

↓

Search Documentation

↓

Read Documentation

↓

Generate Code

↓

Compile Code

↓

Run Tests

↓

Commit Changes

↓

Return Result

Tool chaining is orchestrated by the Planner and executed by the Tool Execution Engine.

63. Parallel Execution

Independent tools may execute concurrently.

Example:

             Planner
                │
     ┌──────────┼──────────┐
     ▼          ▼          ▼
 Search      Database     GitHub
     │          │          │
     └──────────┼──────────┘
                ▼
         Result Aggregator
                │
                ▼
          Final Response

Parallel execution reduces workflow latency while preserving deterministic result aggregation.

64. Checkpoint Integration

Long-running tool executions participate in workflow checkpointing.

Checkpoint lifecycle:

Tool Started

↓

Progress Saved

↓

Checkpoint Created

↓

Worker Failure

↓

Checkpoint Restored

↓

Execution Resumed

Checkpoint support is optional and declared in the tool manifest.

65. Distributed Execution

Tool execution can occur on remote workers.

Agent Runtime

↓

Tool Dispatcher

↓

Scheduler

↓

Worker Lease

↓

Remote Tool Execution

↓

Result Returned

Distributed execution enables horizontal scaling for compute-intensive tools.

66. Caching

Frequently executed tools may cache results.

Supported cache strategies:

In-memory
Redis
Distributed Cache
Persistent Cache

Example:

cache:

  enabled: true

  ttl: 10m

  strategy: redis

Cache invalidation is configurable per tool.

67. Rate Limiting

Rate limiting protects internal and external resources.

Supported scopes:

Platform
Organization
Project
Agent
User
Tool

Example:

rateLimit:

  requestsPerMinute: 300

  burst: 50

Requests exceeding limits receive a standardized throttling response.

68. Testing Strategy

Unit Tests

Verify:

Tool metadata
Input validation
Output validation
Error handling
Permission checks
Serialization

Integration Tests

Verify:

Registry integration
Sandbox execution
Secret resolution
Policy enforcement
Event publishing
Metrics collection

End-to-End Tests

Validate complete execution flows.

Examples:

Agent → Tool → Database
Agent → Tool → Kubernetes
Agent → Tool → GitHub
Multi-tool orchestration
Workflow checkpoint recovery

Performance Tests

Stress-test scenarios include:

100,000 tool registrations
1,000 concurrent executions
Streaming responses > 1 GB
Large payload validation
High-frequency tool discovery

Performance testing ensures predictable latency under production workloads.

Chaos Tests

Inject failures into:

Tool process crashes
Sandbox failures
Registry outages
Secret provider failures
Network partitions
Storage failures
Worker restarts

The framework must recover gracefully without data corruption.

69. Performance Targets

Metric	Target
Registry lookup	< 2 ms
Permission evaluation	< 5 ms
Tool dispatch	< 10 ms
Sandbox allocation	< 100 ms
Tool startup (native)	< 20 ms
Tool startup (container)	< 500 ms
Streaming latency	< 50 ms
Event publication	< 5 ms

70. Security Requirements

The Tool Framework shall provide:

Mutual TLS (mTLS)
Role-Based Access Control (RBAC)
Attribute-Based Access Control (ABAC)
Secret isolation
Audit logging
Network isolation
Filesystem isolation
Resource quotas
Digital signature verification
Supply chain validation

All tools must be signed before production deployment.

71. Scalability

The framework must support:

Millions of registered tools
Thousands of concurrent agents
Horizontal worker scaling
Distributed registries
Multi-region deployments
Multi-cloud execution

There is no architectural limit on the number of tool implementations.

72. Non-Functional Requirements

Requirement	Target
Availability	99.99%
Horizontal scalability	Unlimited
Tool isolation	100%
Permission enforcement	100%
Schema validation	100%
Audit coverage	100%
Secret leakage	0
Deterministic execution	Required where applicable

73. Dependencies

This document depends on:

docs/03-workflow-engine/agent-runtime.md
docs/03-workflow-engine/event-bus.md
docs/03-workflow-engine/persistence-layer.md
docs/03-workflow-engine/distributed-execution.md

docs/04-agent-framework/agent-definition.md
docs/04-agent-framework/memory-system.md
docs/04-agent-framework/planning-engine.md
docs/04-agent-framework/provider-sdk.md
docs/04-agent-framework/policy-engine.md
docs/04-agent-framework/context-manager.md
docs/19-implementation-guide/build-system.md (planned: Rust SDK)

75. Future Enhancements

Planned capabilities include:

Visual Tool Designer
Tool Marketplace
Automatic Tool Discovery
AI-Assisted Tool Generation
WASM-native Tool Runtime
GPU Tool Scheduling
Zero-Trust Tool Execution
Federated Tool Registries
Remote Tool Streaming
Tool Dependency Graphs
Semantic Tool Search
Tool Cost Optimization
Autonomous Tool Selection
AI-Based Failure Recovery

76. Glossary

Term	Definition
Tool	Executable capability exposed to an AI agent
Registry	Catalog of all available tools
Dispatcher	Component that selects and invokes tools
Sandbox	Isolated execution environment
Capability	Feature advertised by a tool
Manifest	Declarative configuration for a tool
Plugin	Deployable package containing one or more tools
Context	Immutable execution metadata passed to a tool
Policy	Security and governance rules
Execution ID	Unique identifier for a tool invocation

77. Revision History

Version	Date	Description
1.0.0	2026-06-26	Initial Tool Framework Specification

Document Summary

This specification defines the complete Tool Framework for the Wovyr AI Platform, including:

Tool lifecycle management
Registry and discovery
SDK architecture
Security and permission model
Sandboxed execution
Streaming support
Distributed execution
Checkpoint integration
Rust SDK interfaces
Plugin architecture
Observability
Testing strategy
Performance targets
Future roadmap

The Tool Framework serves as the foundation for secure, scalable, and extensible interaction between AI agents and external systems.