nexus-performance

A guide that routes investigations into memory leaks or dependency upgrade risks. A memory leak is unwanted memory growth; dependency analysis checks what may be affected when a software library changes.

In plain words
What is it for?
Use it for memory growth, out-of-memory failures, CPU or latency investigations, query-performance problems, regressions, and checking the impact of upgrading a dependency.
Why use it?
It helps choose the relevant investigation workflow instead of treating every performance or upgrade problem the same way.

Skill for Claude CodeCodex

Part of the nexus plugin — 10 skills, 2 commands, 14 agents 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 skills/aayushostwal/nexus/performance
Any agent
npx skills add aayushostwal/nexus --skill performance
Clone the repo
git clone --depth 1 https://github.com/aayushostwal/nexus

Made for: Claude Code, Codex.

Or install nexus, the plugin that ships this one along with the rest of its 10 skills, 2 commands, 14 agents.

Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 734 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00068 $0.00734
Opus 5 $0.00034 $0.00367
Sonnet 5 $0.00014 $0.00147
Haiku 4.5 $0.00007 $0.00073

Measured 3d ago against content hash 6000871ccd1b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nexus-performance scanned grade A with 0 findings 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/performance/SKILL.md · 81 lines

How it starts

The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Nexus Performance

Route to the correct sub-skill and follow it end-to-end.


Compatibility

  • Sub-skills: memory-leak.md, dependency-blast-radius.md
  • Supporting files: examples/production-scenarios.md, checklists/performance-checklist.md, heuristics/performance-heuristics.md, anti-patterns/common-mistakes.md, validation/output-validation.md
  • Required tools: Read, Bash, Grep
  • Hands off to: nexus:debugging for single-service runtime failures
  • Hands off to: the roadmap-planner agent after the fix is approved

Routing

Step 1 — Classify the Request

Pick exactly one track:

Track Signal Sub-skill
Memory Leak "memory growing", "OOM kill", "heap dump", "RSS increasing", "memory usage creeping up", process being killed by the OS memory-leak.md
Dependency Blast Radius "upgrade X to version Y", "what breaks if I upgrade", "which services use this lib", "blast radius of upgrading", "safe to upgrade?", "dependency impact analysis" dependency-blast-radius.md

If the request does not clearly fit one track, ask one question: "Is this about memory/CPU/latency behavior of a running service, or about the risk of upgrading a dependency?"

Step 2 — Read Sub-Skill and Execute

Read the appropriate sub-skill file. Follow its numbered steps in order. Do not skip steps. Read heuristics/performance-heuristics.md for fast pattern-matching before starting investigation.

Step 3 — Validate Output

Before presenting results, check against validation/output-validation.md.


Output Format

Each sub-skill defines its own output format. This router produces no standalone output.


Anti-Patterns

  • Never profile a running production process without confirming the profiling overhead is acceptable.
  • Never recommend a dependency upgrade without completing the blast radius analysis first.
  • Never mix tracks — complete one sub-skill fully before considering another.
  • Never skip reading the actual code or configuration — performance issues are almost always specific to the exact version and usage pattern.
  • Never recommend "just increase memory/CPU limits" without first identifying the root cause — scaling a leak just delays the next OOM.

Read the full file on GitHub · 81 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 81 lines · 68 tokens per session scan A 6000871ccd1b

Subscribe to this mod's changes

nexus-performance is a skill published in the GitHub repository aayushostwal/nexus (18 stars, last pushed 23d ago), licensed MIT. It adds 68 tokens to every session and 734 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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