Ch6. Context, Skills, Dynamic Capabilities

Agent quality is often constrained more by context design than by the model. Eve provides several context surfaces so you do not have to put everything into one prompt.

Context Levers

Instructions Stay Short And Stable

Good instructions establish durable behavior:

You are the internal release operations agent.

Rules:
- Never perform external write actions without explicit approval.
- Prefer reading repository and deployment evidence before recommending rollback.
- If policy is missing, ask a clarifying question instead of guessing.

Do not bury long procedures in always-on instructions. Move procedures to skills.

Skills Are Procedure Memory

Skills are loaded on demand. Use them for:

• incident playbooks
• release checklists
• customer-support policy
• data analysis procedures
• domain-specific formatting rules

Skill files can be markdown or TypeScript-defined skills. The important part is a precise description.

Skill Description Is A Routing Contract

The model chooses when to load skills based on this contract.

Dynamic Tools

Dynamic tools let a resolver return tool definitions at runtime.

import { defineDynamic } from "eve/tools";

export default defineDynamic(async (ctx) => {
  const plan = ctx.session.auth.current?.attributes.plan;
  if (plan !== "enterprise") return {};

  return {
    export_audit_report: {
      description: "Export an audit report for the current tenant.",
      inputSchema: z.object({ range: z.string() }),
      execute: async (input) => exportAuditReport(input),
    },
  };
});

Dynamic tool execute functions must be inline so the runtime can carry the definition across step boundaries.

Dynamic Naming

Dynamic tool names become <fileSlug>__<key>. This makes collisions less likely but also means naming affects traces and evals.

Dynamic Skills And Instructions

Use dynamic skills/instructions when the policy or procedure depends on runtime context.

import { defineDynamic } from "eve/instructions";

export default defineDynamic(async (ctx) => {
  const tier = ctx.session.auth.current?.attributes.plan ?? "unknown";
  return `The caller plan is ${tier}. Apply the matching support policy.`;
});

Guideline: dynamic instructions should be short facts or policy pointers, not full knowledge bases.

Event Order

Channel handlers update state before hooks and dynamic resolvers read it. This enables a channel to project metadata and dynamic capabilities to use that metadata.

Example:

1. Slack mention arrives.
2. Channel handler loads thread context and updates channel state.
3. Stream event is recorded.
4. Hooks run.
5. Dynamic resolvers read projected channel metadata.

Prevent Context Pollution

Evaluation Criteria