`agent` with ReAct strategy, tool catalogue, and budgets

Primitives used: persona · tool · memory · shield · agent

// `agent` is the v1.12.0+ orchestrated cognitive entity. Where
// `persona` declares identity and `flow` declares a typed sequence,
// `agent` binds tools + memory + shield under a coordination
// strategy (react | plan_and_execute | reflexion | custom) with
// explicit budgets.

persona Researcher {
    domain: ["research"]
    tone: analytical
    confidence_threshold: 0.85
    cite_sources: true
}

tool WebSearch {
    // LLM-routed: the tool IS the model. No `provider:` (v2.69.0).
    effects:  <network>
    timeout:  30s
}

tool Calculator {
    // LLM-routed: the tool IS the model. No `provider:` (v2.69.0).
    effects:  <pure>
    timeout:  5s
}

memory SessionScratch {
    store:     session
    retrieval: semantic
}

shield SafeAgent {
    scan:       [prompt_injection, data_exfil]
    on_breach:  halt
    severity:   high
    compliance: [SOC2]
}

agent ResearchAssistant {
    goal:           "Answer user questions by combining web search with arithmetic."
    tools:          [WebSearch, Calculator]
    memory:         SessionScratch
    strategy:       react
    on_stuck:       escalate
    shield:         SafeAgent
    max_iterations: 12
    max_tokens:     16384
    max_time:       2m
}