writing-plans

If activation mode is explicit (`~/.config/aegis/config.toml` has `activation_mode = "explicit"`, or `AEGIS_ACTIVATION_MODE=explicit` is visible in the environment) and the current user request did not explicitly invoke Aegis or this skill by name, exit back to the fast path: answer concisely without this workflow's checklist, ceremony, or document requirements. If the user explicitly named Aegis or this skill, proceed normally.

Execute

→ Existing parent plan/spec and a tiny execution slice? → Use Planless Slice Lane. → Mechanical or bounded change with no durable boundary (no new owner, contract, schema, public API, migration, or compat surface)? → Use Planless Slice Lane without a parent document. → Approved spec/requirements for a new workstream or an escalation trigger? → Write an implementation plan for an engineer with no prior task context.

For a durable plan: confirm scope and acceptance, map current owners/files, record the TDD route, decompose into executable tasks, define verification and retirement, self-review, save, then select the execution route. Proceed unless a real authorization or safety boundary requires the user.

Escalate from Planless Slice Lane when the work adds a new owner, contract, schema, public API, architecture boundary, migration, persistence, security/permission, distribution/release surface, or an unclear verification boundary.

Writing Plans

This skill turns approved requirements into a bounded, executable plan. The plan must answer: what changes, why code is necessary, which existing owner and files change, what stays compatible, what verifies the result, what risk remains, and what old path is retired or deliberately retained. A plan is method-pack guidance; it cannot grant authoritative completion.

TDD Route Guard

Before task decomposition, record TDD Route with mode (off | auto), decision (strict | light | skipped), authority, test posture, reason, and verification.

Strict RED / GREEN steps belong only to an explicit user/project TDD request or TDD Route: strict. In off, use skipped unless explicit strict authority overrides it. An approved plan or a risk label alone is not strict authority.

In auto, select strict for behavior, bugfix, shared/core, contract, persistence, permission, migration, producer/consumer, or meaningful regression signals. Select light only when the work is tiny, low-risk, single-owner, has no behavior change or strict signal, and has an obvious focused check. Absence of an explicit user TDD request is never evidence for light; the auto decision itself must be recorded.

If risk remains unknown, return to requirements, debugging, or plan review before task decomposition; do not infer a TDD route from uncertainty.

Only a strict decision with stated authority may prescribe failing-test, RED, GREEN, and REFACTOR steps. Otherwise plan the minimum change plus diagnostic reproduction or post-change regression. A missing auto decision returns to route selection before implementation tasks.

Entry And Artifact Choice

Announce at start: on the plan-writing route, say that this skill is creating the implementation plan. On Planless Slice Lane, announce the lane instead and do not claim a plan is being created.

Execution context: Reuse the current branch/workspace by default. A branch needs independent history; a worktree needs concurrent checkout, blocking unrelated dirty state, or explicit user/repository authority.

Input: approved requirements, a Spec Brief, or a Design Spec.

Default plan path: docs/aegis/plans/YYYY-MM-DD-<feature-name>.md. Plans do not go in work/; user and repository authority override the default.

Exception: use Planless Slice Lane when an existing parent plan/spec already owns the current tiny execution slice, or when the change is mechanical or bounded and needs no parent document. Do not save a new plan. Emit a compact Slice Card:

Slice Card:
- Goal:
- Parent plan/spec:
- Files:
- Boundary:
- Verification:
- Stop:

On the no-parent branch, Parent plan/spec: is none — direct bounded request.

Aegis Project Workspace

Workspace creation is lazy and follows project authority. The Aegis Method Pack repository must not create or ship a live docs/aegis/ workspace. When a durable plan must initialize or update another project's workspace, read the workspace section of expanded-planning-guidance.md. It owns the <aegis-workspace-helper> and INDEX.md command detail, not the decision to create a plan.

Default Plan Surface

Compact output contract: express these as natural plan content, not a stack of cards: Aegis Visibility, approved scope and plan basis, required baseline refs, files/owners, compatibility boundary, Change Necessity, TDD route, tasks, verification, risks, and retirement. Keep conditional structures silent unless their trigger below fires.

Aegis Visibility is normally one sentence explaining which owner, contract, retirement, compatibility, or verification pressure makes a durable plan useful. Structured trace belongs only to audit, debug, release, long-task review, or explicit request.

Before tasks, perform a Requirement Ready Check: identify the approved source, scope, scenarios, and acceptance evidence. If any decision-changing item is missing, do not create implementation tasks; return the smallest gap to the requirement/spec owner.

Perform Change Necessity before any non-trivial source edit or any new source-code path. This is behavior-triggered, not prompt-triggered. State naturally why no-change/docs/config is insufficient and name the minimum code boundary. A tiny helper, guard, branch, fallback, adapter, or owner is not exempt. A no-change, docs/config-only, or needs-clarification result narrows or stops the code plan.

Run Ripple Signal Triage before tasks when the change touches shared/core or cross-module behavior; a public API, schema, contract, compatibility, persistence, cache, export/readback, fallback, adapter, duplicate/legacy owner, retirement path, or both producer and consumer. If no signal fires, add no output. If one fires, identify the canonical owner and affected downstream consumers, state source-of-truth/contract/fallback/retirement risk, and carry expanded verification into the relevant task. A required owner/public-contract/source-of-truth change, retaining two owners, or adding a fallback, adapter, or compatibility branch returns to design or requires explicit prior alignment before implementation.

Run a compact Plan Pressure Test before task decomposition: test owner / contract / retirement fit, higher-level architecture path, verification scope, and task executability. It may proceed, revise the plan, or return to design; it is not an approval authority.

Conditional Detailed Guidance

For interface/interaction work, compose ui-ux-governance and carry the accepted experience criteria and corresponding checks into affected tasks. Include API changes that alter visible states or recovery; keep backend-only work scoped.

Read only the trigger-matched section of expanded-planning-guidance.md:

• ## Baseline And Requirement Detail when specific baseline acknowledgement needs structure or requirement readiness is incomplete/disputed;
• ## New-Surface And Architecture Detail when a new surface or new owner needs Existence Check, AEGIS_MINIMALITY_REFERENCE, Architecture Integrity Lens, or first-principles-review detail before task decomposition;
• ## Complexity Detail when material file-size, mixed-owner, add-in-place, adapter, fallback, or shared-core pressure appears;
• ## Execution Readiness Detail for a long-running, handoff-prone, subagent-driven, high-risk architecture/contract/compatibility/retirement handoff;
• ## Workspace Save Detail only when saving requires workspace initialization or INDEX.md updates;
• ## Execution Route Detail only when route evidence needs a structured handoff; and
• ## Expanded Plan Review only for an independent high-risk or handoff-heavy review.

The direct triggers cover baseline readiness, new surface or new owner, complexity pressure, workspace persistence, and execution handoff. The reference supplies detail only. This main file owns routing, plan versus Planless selection, task blocking, and execution handoff.

For a new surface, use Existence Check and docs/current/AEGIS_MINIMALITY_REFERENCE.md before tasks. Reuse an existing owner when it is sufficient. If owner, contract, responsibility overlap, higher-level simplification, fallback, or retirement remains risky, use the Architecture Integrity Lens and first-principles-review before task decomposition.

For maintained source, screen file shape, owner fit, add-in-place risk, and a better boundary. With no pressure signal, a compact edit-in-place decision is enough. When pressure exists, load the expanded Plan-Time Complexity Check and Complexity Budget. An over-budget result must change the task boundary, add governance work, or stop for follow-up.

For an ordinary medium/high handoff, state Intent Lock, Scope Fence, Baseline Lock, tests, and drift stop naturally. Load the expanded Execution Readiness View only for the auditable handoff triggers above. Neither form is a GateDecision, PolicySnapshot, approval gate, or completion authority.

If the plan must choose among deleting an old internal path, retaining a proven external compatibility boundary, or stopping for persistent-state confirmation, compose anti-entropy-governance. It does not authorize destructive execution.

Preserve approved ADR signal preservation, source refs, alternatives, compatibility, and baseline-sync questions for completion; do not create accepted architecture memory from an unexecuted plan.

Planless Slice Lane

Use Planless Slice Lane before writing or saving a plan when one of these entry conditions holds:

• a parent spec or parent plan already defines the workstream, and the current request is executing or refining one bounded task from that parent
• the change is mechanical or bounded and needs no parent document (the no-parent branch under # Execute)

and both of these are true:

• no new owner, contract, schema, public API, architecture boundary, migration, persistence, security/permission, distribution/release surface, or unclear verification boundary appears
• the slice can be described by a Slice Card

The lane preserves long-task continuity without turning execution bookkeeping into durable planning artifacts. A parent scope or acceptance mismatch returns to the parent plan/spec instead of spawning a micro-plan.

Plan And Task Quality

Map files before tasks. Follow existing ownership and naming. For non-trivial plans, passively use relevant current terms from CONTEXT-MAP.md or CONTEXT.md; route a real semantic conflict to establishing-project-context.

Every durable plan starts with Goal, Architecture, Tech Stack, Baseline/Authority Refs, Compatibility Boundary, TDD Route, and Verification. Then define small, ordered tasks with exact files, purpose, minimum necessary change, compatibility impact, and commands/outcomes that prove the task. Include code excerpts only when a signature, contract, or transformation would otherwise remain ambiguous; do not duplicate the implementation inside the plan.

For bug fixes, refactors, contract changes, or governance cleanup, keep Repair Track and Retirement Track explicit in the affected task. A retained old owner or fallback needs a reason and retirement trigger.

Self-review once for approved-scope coverage, placeholders, owner/type consistency, minimum change boundary, compatibility, exact verification, conditional trigger handling, and retirement. Fix defects inline. Tasks are execution units, not Git history units: the coordinator captures TaskStartSnapshot and creates one scoped commit only after the whole Task is reviewed and freshly verified.

Execution Handoff

The agent owns the execution-route decision. Select subagent-driven only for genuinely independent tasks with bounded ownership when coordination pays for it; otherwise select inline. Unavailable subagents falls back to inline execution. A dirty workspace alone does not select either route.

Ask the user only for unresolved authorization, privacy, paid-resource, external-action, irreversible-action, scope, acceptance, or workspace-ownership boundaries. Otherwise proceed immediately. State the decision, evidence, fallback, and User confirmation required: no | yes — <boundary> compactly; load the reference only when the full Execution Route schema is useful.

For subagent-driven, use aegis:subagent-driven-development. For inline, use aegis:executing-plans.