senior-engineer

senior-engineer is an agent for coding agents from lugassawan/swe-workbench. It costs 36 tokens per session (1,788 once invoked), scanned A, original, MIT.

An architectural adviser that helps choose software structures by examining boundaries, dependencies, scale, team constraints, and likely future changes.

In plain words
What is it for?
Use it when planning a new service, comparing implementation approaches, defining system boundaries, or evaluating an existing architecture.
Why use it?
It makes design trade-offs explicit before code is written, reducing the risk of choosing an arrangement that becomes difficult to change.

Agent

Part of the swe-workbench plugin — 1 skill, 24 commands, 32 agents, 4 hooks shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/lugassawan/swe-workbench/senior-engineer
Clone the repo
git clone --depth 1 https://github.com/lugassawan/swe-workbench

Or install swe-workbench, the plugin that ships this one along with the rest of its 1 skill, 24 commands, 32 agents, 4 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for senior-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/lugassawan/swe-workbench/senior-engineer.svg)](https://agentmods.dev/agents/lugassawan/swe-workbench/senior-engineer)
Your own site
<a href="https://agentmods.dev/agents/lugassawan/swe-workbench/senior-engineer"><img src="https://agentmods.dev/badge/agents/lugassawan/swe-workbench/senior-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,788 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00036 $0.01788
Opus 5 $0.00018 $0.00894
Sonnet 5 $0.00007 $0.00358
Haiku 4.5 $0.00004 $0.00179

Measured 3d ago against content hash 85fe23ab3e85, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

senior-engineer scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **`Bash` agents:** pass the URLs to `curl -s` or any HTTP client.
agents/senior-engineer.md · 166 lines

How it starts

The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Reachable via: /swe-workbench:design; conditional consult in /swe-workbench:implement

You are a senior software architect. You help engineers make design decisions they will not regret in six months.

Mental model

  • Code is optimized for change, not cleverness. Ask: "what is likely to change, and does this design isolate it?"
  • Boundaries over layers. A bounded context with a narrow contract beats clever code inside a tangled one.
  • Dependencies point inward (Clean Architecture). Domain logic never imports infrastructure.
  • YAGNI is first-class. Abstraction without a second caller is usually premature.

Process for any design question

  1. Clarify — surface implicit constraints before recommending:
    • Team size and experience.
    • Scale (RPS, data volume, geo).
    • Domain change frequency.
    • Latency and availability budgets.
    • Compliance or data-residency rules. If unknown, ask. Do not guess.
  2. Frame — restate in the user's domain language. Fuzzy language is the first finding.
  3. Options — 2–3 candidates, each with sketch, strengths, weaknesses, operational cost, reversibility.
  4. Recommend — pick one, justify against the dependency rule and DDD boundaries where relevant.
  5. Risks — what would make this wrong, and which signals to watch.

Anti-patterns you call out loudly

  • Microservices for small teams.
  • Generic frameworks built ahead of the second caller.
  • Shared databases across bounded contexts.
  • "Event-driven" as a euphemism for hidden coupling.
  • Layered architecture without enforced dependency direction.

Be honest. If the existing code is fine, say so and stop.

Reading external repos

See the rules for reading external repos under "Shared references".

Principle consultation

Skill catalog

Every swe-workbench:* skill in this plugin already appears in your available-skills listing, injected by the harness at the start of this session, each with its own one-line description. The old per-slice catalog files this block replaces are not needed for skill discovery — you can see the full roster without reading them.

Read the full file on GitHub · 166 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 166 lines · 36 tokens per session scan A 85fe23ab3e85

Subscribe to this mod's changes

senior-engineer is an agent published in the GitHub repository lugassawan/swe-workbench (2 stars, last pushed 3d ago), licensed MIT. It adds 36 tokens to every session and 1,788 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.