dotnet-explore

A read-only navigator for unfamiliar C# and .NET code. It finds relevant symbols, where they are used, the files involved, and the likely scope of a change.

In plain words
What is it for?
Surveying .NET subsystems, locating code for a new feature, tracing references, and checking the likely impact of a refactor.
Why use it?
It helps developers understand an unfamiliar codebase before editing it and see what else a change may affect.

Skill for Claude CodeCodex

Part of the dotnet-toolkit plugin — 9 skills, 6 agents, 2 hooks, 1 MCP server 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/attemainio/dotnet-toolkit/dotnet-explore
Any agent
npx skills add Attemainio/dotnet-toolkit --skill dotnet-explore
Clone the repo
git clone --depth 1 https://github.com/Attemainio/dotnet-toolkit

Made for: Claude Code, Codex.

Or install dotnet-toolkit, the plugin that ships this one along with the rest of its 9 skills, 6 agents, 2 hooks, 1 MCP server.

Per session 104 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,246 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 $0.00104 $0.01246
Opus 5 $0.00052 $0.00623
Sonnet 5 $0.00021 $0.00249
Haiku 4.5 $0.00010 $0.00125

Measured 2d ago against content hash 769809951cfe, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dotnet-explore 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.

skills/dotnet-explore/SKILL.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Delegating the sweep to dotnet-explore

This plugin ships one read-only navigator subagent, dotnet-explore. It turns a prose task into the symbols it is about: symbolIds, use sites, affected files, and how far a change would reach. It never judges code and it cannot change it — the invoking agent decides what to do with the map.

Why delegate rather than fan out yourself. A wide search_index plus a get_references per candidate is the single most expensive shape of read this server produces, and almost all of those tokens are scaffolding you throw away once you know the answer. The agent pays them in its own context and returns a report a fraction of the size.

When to invoke it — and when not to

Invoke it when the symbol set is genuinely unknown: an unfamiliar subsystem, "how would this feature land", "what breaks if I change this", a review or refactor whose boundary you cannot yet name.

Skip it when:

  • The symbol is already known. A two-call lookup is not what this is for; use dotnet-read.
  • The next step needs a contentVersion. The agent is instructed never to report one — it is an edit lease that goes stale the moment anything moves, and a patch built on a relayed one gets stale_base at best and a silent revert at worst. You fetch your own with get_symbol.
  • The answer is in a non-C# file. .csproj, .json, .md, .editorconfig are out of its scope; it will say so and stop.

Step 0 — check readiness before launching

Call workspace_status yourself, before spawning. The agent checks too, but a cold or degraded workspace wastes an entire agent run:

  • Still loading, or index_only → semantic results are unavailable, not empty. Wait, or accept a syntax-tier map and say so.
  • degraded (projects failed to load) → the map may be silently wrong. Fix the build and reload_workspace before spawning, or don't spawn.
  • Just did a git pull/checkout/rebase, or added or deleted a .cs file → reload_workspace(scope: "all") first.

Read the full file on GitHub · 88 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. 2d ago First seen · 88 lines · 0 tokens per session scan A 769809951cfe

Subscribe to this mod's changes

dotnet-explore is a skill published in the GitHub repository Attemainio/dotnet-toolkit (2 stars, last pushed 6d ago), licensed MIT. It adds 104 tokens to every session and 1,246 once invoked, about $0.0005 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.

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