Summary

Document the Hermes tool-time principle established in #17459:

Runtime time, timezone, and contact-window facts should be surfaced to the agent/tool result as context. Hermes core should not silently enforce quiet-hours policy in the control plane by default.

The repo currently does not appear to contain TOOL-PRINCIPLES.md, but this architectural decision needs a durable home so future PRs do not reintroduce hidden quiet-hours enforcement.

Why

Several related PRs/issues try to solve time awareness in different layers. Without a written principle, it is easy to regress toward gateway/control-plane suppression or duplicated timestamp-prefix mechanisms.

Proposed docs

Add or update docs that state:

1. Stable cached prompt: volatile current time does not belong in the cached system prompt.
2. Agent-visible runtime context: current time/timezone/contact-window facts should be injected through the chosen ephemeral runtime context path and/or returned by relevant tools.
3. Advisory by default: tools may warn when an action appears outside the user's normal contact window, but Hermes core should not silently block, queue, or rewrite the action unless an explicit tool/user policy asks for that.
4. One core path: avoid multiple gateway-specific timestamp-prefix mechanisms when a core ephemeral context path exists.
5. Tool extension point: document how new time-sensitive tools should use the shared time-advisory helper.

Acceptance criteria

• Add a durable docs page/file for tool-use/time-policy principles.
• Link Rework quiet-hours/time awareness: surface time to agent/tools, don't enforce in control plane #17459 as the umbrella issue.
• Document non-goals: no broad policy engine, no hidden quiet-hours enforcement, no volatile time in cached system prompt.
• Cross-link from relevant tool/gateway docs.
• Include a short checklist for reviewers evaluating time-sensitive tools.

Related

Parent: #17459
Related: #10421, #15872, #17335