MCP-Atlas

phone-crime-oldest-woman-suspect

I have a record in my local files about a criminal phone incident from the past where the person believed to be responsible was a woman, the oldest such individual recorded in the file, who has not been aprehended yet. Tell me the number of reported instances per 10 thousand people related to the global health crisis happening during the year this crime took place, considering only the three month standard yearly period where this date would be included. The information for data related to this health crisis is also in my local files.

Task Prompt

I have a record in my local files about a criminal phone incident from the past where the person believed to be responsible was a woman, the oldest such individual recorded in the file, who has not been aprehended yet.

Tell me the number of reported instances per 10 thousand people related to the global health crisis happening during the year this crime took place, considering only the three month standard yearly period where this date would be included. The information for data related to this health crisis is also in my local files.

VFS.md

---
name: workspace-filesystem
description: The virtual filesystem layout of this workspace.
---

# Virtual Filesystem

You work in a terminal over a virtual filesystem. Read files with shell
commands.

Command output comes back whole, however long. Some files here are large,
so point `grep -r`, `rg`, `find` and `cat` at the directory or file you
need rather than at a whole mount.

| path | what it is |
|---|---|
| `/data` | Your files. |
| `/mongodb` | Your MongoDB databases, read-only; change them with the `mongodb` CLI. |
| `/tmp` | Scratch space, in memory. |

## `/mongodb`

```
/mongodb/
  <database>/
    database.json
    collections/
      <collection>/
        schema.json
        documents.jsonl
    views/
      <view>/
        schema.json
        documents.jsonl
```

- `database.json`: `{database: str, collections: list[{name: str}],
  views: list[{name: str}]}`
- `schema.json`: `{database: str, name: str, kind: str, validator: dict |
  null, fields: list[{path: str, presence: number, types: dict}],
  primary_key: str, indexes: list[{name: str, keys: dict, type: str}],
  sampled: int}`, read from a sample of `sampled` documents
- `documents.jsonl`: one document per line, in MongoDB Extended JSON: a date
  reads as `{"$date": "..."}`

name	workspace-filesystem
description	The virtual filesystem layout of this workspace.

Virtual Filesystem

You work in a terminal over a virtual filesystem. Read files with shell commands.

Command output comes back whole, however long. Some files here are large, so point grep -r, rg, find and cat at the directory or file you need rather than at a whole mount.

path	what it is
`/data`	Your files.
`/mongodb`	Your MongoDB databases, read-only; change them with the `mongodb` CLI.
`/tmp`	Scratch space, in memory.

/mongodb

/mongodb/
  <database>/
    database.json
    collections/
      <collection>/
        schema.json
        documents.jsonl
    views/
      <view>/
        schema.json
        documents.jsonl

database.json: {database: str, collections: list[{name: str}], views: list[{name: str}]}
schema.json: {database: str, name: str, kind: str, validator: dict | null, fields: list[{path: str, presence: number, types: dict}], primary_key: str, indexes: list[{name: str, keys: dict, type: str}], sampled: int}, read from a sample of sampled documents
documents.jsonl: one document per line, in MongoDB Extended JSON: a date reads as {"$date": "..."}

SKILL.md

---
name: workspace-commands
description: Use when running commands in this workspace - which commands exist, what they can do, and what the interpreter supports.
---

# Available commands

Python (`python` or `python3`), Perl, JavaScript/Node.js, and TypeScript
runtimes are unavailable. Use the shell commands and task CLIs documented
below; do not probe for or attempt to install other runtimes.

Standard Unix commands, among them:

    cat  head  tail  ls  find  grep  wc  sort  uniq  cut  tr  sed  awk
    diff  tee  xargs  jq

with pipes, `>` redirection and `$(...)` substitution.

Do not probe the machine with `which`, `type`, `--version`, `env`, `ps`,
`echo $PATH`, `ls /usr/bin` or `cat /usr/bin/<command>`: they tell you
nothing about the task.

A filename with a space in it needs quoting, as it would in any shell.

## mongodb

Use `mongodb <command> '<JSON arguments>'`. Run `mongodb <command> --help`
to get more information.

```sh
mongodb list-collections '{"database":"DATABASE"}'
mongodb list-databases '{}'
mongodb collection-indexes '{"database":"DATABASE","collection":"COLLECTION"}'
mongodb collection-schema '{"database":"DATABASE","collection":"COLLECTION"}'
mongodb find '{"database":"DATABASE","collection":"COLLECTION","filter":{"FIELD":"VALUE"},"limit":10}'
mongodb count '{"database":"DATABASE","collection":"COLLECTION","query":{"FIELD":"VALUE"}}'
```

| Command | Arguments | Description |
|---|---|---|
| `mongodb list-collections` | `{database: str}` | List all collections for a given database |
| `mongodb list-databases` | `{}` | List all databases for a MongoDB connection |
| `mongodb collection-indexes` | `{database: str, collection: str}` | Describe the indexes for a collection |
| `mongodb collection-schema` | `{database: str, collection: str}` | Describe the schema for a collection |
| `mongodb find` | `{database: str, collection: str, filter?: dict, projection?: dict, limit?: number = 10, sort?: dict}` | Run a find query against a MongoDB collection |
| `mongodb count` | `{database: str, collection: str, query?: dict}` | Gets the number of documents in a MongoDB collection using db.collection.count() and query as an optional filter parameter |

## wikipedia

Use `wikipedia <command> '<JSON arguments>'`. Run
`wikipedia <command> --help` to get more information.

```sh
wikipedia search-wikipedia '{"query":"QUERY"}'
wikipedia get-article '{"title":"TITLE"}'
```

| Command | Arguments | Description |
|---|---|---|
| `wikipedia search-wikipedia` | `{query: str, limit?: int = 10}` | Search Wikipedia for articles matching a query. |
| `wikipedia get-article` | `{title: str}` | Get the full content of a Wikipedia article. |

## exa

Use `exa <command> '<JSON arguments>'`. Run `exa <command> --help` to get
more information.

```sh
exa web-search-exa '{"query":"QUERY","numResults":5}'
```

| Command | Arguments | Description |
|---|---|---|
| `exa web-search-exa` | `{query: str, numResults?: number}` | Search the web for any topic and get clean, ready-to-use content. |

## e2b-server

Use `e2b-server <command> '<JSON arguments>'`. Run
`e2b-server <command> --help` to get more information.

```sh
e2b-server run-code '{"code":"print(1 + 1)"}'
```

| Command | Arguments | Description |
|---|---|---|
| `e2b-server run-code` | `{code: str}` | Run python code in a secure sandbox by E2B. Using the Jupyter Notebook syntax. |

name	workspace-commands
description	Use when running commands in this workspace - which commands exist, what they can do, and what the interpreter supports.

Available commands

Python (python or python3), Perl, JavaScript/Node.js, and TypeScript runtimes are unavailable. Use the shell commands and task CLIs documented below; do not probe for or attempt to install other runtimes.

Standard Unix commands, among them:

cat  head  tail  ls  find  grep  wc  sort  uniq  cut  tr  sed  awk
diff  tee  xargs  jq

with pipes, > redirection and $(...) substitution.

Do not probe the machine with which, type, --version, env, ps, echo $PATH, ls /usr/bin or cat /usr/bin/<command>: they tell you nothing about the task.

A filename with a space in it needs quoting, as it would in any shell.

mongodb

Use mongodb <command> '<JSON arguments>'. Run mongodb <command> --help to get more information.

mongodb list-collections '{"database":"DATABASE"}'
mongodb list-databases '{}'
mongodb collection-indexes '{"database":"DATABASE","collection":"COLLECTION"}'
mongodb collection-schema '{"database":"DATABASE","collection":"COLLECTION"}'
mongodb find '{"database":"DATABASE","collection":"COLLECTION","filter":{"FIELD":"VALUE"},"limit":10}'
mongodb count '{"database":"DATABASE","collection":"COLLECTION","query":{"FIELD":"VALUE"}}'

Command	Arguments	Description
`mongodb list-collections`	`{database: str}`	List all collections for a given database
`mongodb list-databases`	`{}`	List all databases for a MongoDB connection
`mongodb collection-indexes`	`{database: str, collection: str}`	Describe the indexes for a collection
`mongodb collection-schema`	`{database: str, collection: str}`	Describe the schema for a collection
`mongodb find`	`{database: str, collection: str, filter?: dict, projection?: dict, limit?: number = 10, sort?: dict}`	Run a find query against a MongoDB collection
`mongodb count`	`{database: str, collection: str, query?: dict}`	Gets the number of documents in a MongoDB collection using db.collection.count() and query as an optional filter parameter

wikipedia

Use wikipedia <command> '<JSON arguments>'. Run wikipedia <command> --help to get more information.

wikipedia search-wikipedia '{"query":"QUERY"}'
wikipedia get-article '{"title":"TITLE"}'

Command	Arguments	Description
`wikipedia search-wikipedia`	`{query: str, limit?: int = 10}`	Search Wikipedia for articles matching a query.
`wikipedia get-article`	`{title: str}`	Get the full content of a Wikipedia article.

exa

Use exa <command> '<JSON arguments>'. Run exa <command> --help to get more information.

exa web-search-exa '{"query":"QUERY","numResults":5}'

Command	Arguments	Description
`exa web-search-exa`	`{query: str, numResults?: number}`	Search the web for any topic and get clean, ready-to-use content.

e2b-server

Use e2b-server <command> '<JSON arguments>'. Run e2b-server <command> --help to get more information.

e2b-server run-code '{"code":"print(1 + 1)"}'

Command	Arguments	Description
`e2b-server run-code`	`{code: str}`	Run python code in a secure sandbox by E2B. Using the Jupyter Notebook syntax.

VFS passed: 5/5
MCP passed: 5/5
Fewer tokens with VFS: 3 of 5 models

Passes and mean tokens per run for each model, VFS vs MCP
Model	VFS	MCP	VFS Tokens	MCP Tokens	Token Reduction Rate
Claude Opus 5.5	1/1	1/1	16.3k	31.8k	49%
GPT-6.1 Sol	1/1	1/1	8.48k	12.4k	31%
GPT-5.6 Luna	1/1	1/1	62.6k	36.0k	−74%
Claude Haiku 5.5	1/1	1/1	84.5k	39.5k	−114%
Gemini 3.8 Flash	1/1	1/1	1.29M	1.46M	12%