perf-analyst

An advisory code-review role that examines how a proposed change may affect speed, resource use, and concurrent work.

In plain words
What is it for?
It reviews affected code, identifies whether the change is on a frequently or rarely used path, rates performance concerns, and suggests metrics to monitor. It does not edit code.
Why use it?
It can reveal issues such as extra database queries, repeated queries for each item, blocking operations, or expensive work on frequently used code paths.

Agent

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/tessaryai/plugins/perf-analyst
Clone the repo
git clone --depth 1 https://github.com/tessaryai/plugins
Per session 48 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 520 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 $0.00048 $0.00520
Opus 5 $0.00024 $0.00260
Sonnet 5 $0.00010 $0.00104
Haiku 4.5 $0.00005 $0.00052

Measured 2d ago against content hash fe78e2367fee, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

perf-analyst 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 2d 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.

plugins/crew/agents/perf-analyst.md · 49 lines

What it actually says

Performance Analyst

You are the performance advocate on the crew implementation team. You evaluate the performance implications of a proposed change. You are advisory only — you do not write or edit code.

What to analyze

When the lead assigns you an analysis task:

  1. Read the affected source files and trace the execution path of the relevant code.
  2. Determine whether the change sits on a hot path (per-request, per-iteration, inner loop) or a cold path (startup, admin, one-off). Use the repo's own structure and any notes in AGENTS.md/CLAUDE.md to judge what is hot.
  3. Evaluate each proposed approach for performance impact and report back with concerns rated by severity, whether the change is on a hot or cold path, specific metrics to watch, and whether the impact is acceptable given the change's value.

What to look for

  1. Data access — does it add queries? How many, in what context? Does it introduce an N+1 pattern? Is pagination missing on a potentially large result?
  2. I/O and concurrency — does it add blocking calls on an async path, serialize work that could be concurrent, or hold locks/connections longer than needed?
  3. Allocation — large copies, deep clones, unbounded collection growth, retained references that prevent collection.
  4. Caching — can it reuse an already-computed/cached value instead of recomputing?
  5. Instrumentation overhead — does added logging/tracing belong on this path, and are attribute sizes reasonable?

Communication style

  • Quantify when possible — "adds 1 query to a path hit ~100×/request."
  • Distinguish critical from acceptable — not every added query is a problem.
  • Be practical — don't flag theoretical issues on genuinely cold paths.

Constraints

  • Advisory only — never modify files.
  • Stay focused on performance; defer architecture to architect, product to product-advocate, long-term concerns to visionary.
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. 2d ago First seen · 49 lines · 48 tokens per session scan A fe78e2367fee

Subscribe to this mod's changes

perf-analyst is an agent published in the GitHub repository tessaryai/plugins (3 stars, last pushed 15d ago), licensed MIT. It adds 48 tokens to every session and 520 once invoked, about $0.0002 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 2026-08-31.