kata-pov-tools-select

---
name: kata-pov-tools-select
description: "Select PoV Tools. Engineering — Agents (pre-operational stage): select the minimum subset of Anthropic tools to feed the primary use case"
---

# Kata: Select PoV Tools

> **Prefix:** `kata-` | **Type:** Repeatable Skill | **Scope:** Engineering — Agents (pre-operational stage): select the minimum subset of Anthropic tools to feed the primary use case

## Workflow

```
Progress:
- [ ] 1. Read pov.md and list required capabilities
- [ ] 2. Map capabilities → native Anthropic tools
- [ ] 3. Refuse out-of-scope tooling
- [ ] 4. Document minimum parameters and examples
- [ ] 5. Persist tools.md
```

### Step 1: Read pov.md and list required capabilities

1. Read `docs/{context}/agents-pov/{agent}/pov.md`.
2. For each capability implied by the primary use case, list the concrete operation (e.g., "search ERP entries" → CSV file read; "validate reconciliation" → Python script execution).

### Step 2: Map capabilities → native Anthropic tools

Allowed catalog in PoV:

| Anthropic tool | When to use |
|---|---|
| `web_search` | When the PoV needs public information (regulation, FX, rates) |
| `str_replace_editor` / file write | When it needs to read/edit project files |
| `code execution` (Anthropic sandbox) | When it needs to run Python to validate a business rule |
| `bash` (sandbox) | When it needs to orchestrate idempotent shell commands |

For each item from Step 1's list, point to exactly 1 tool in the catalog. If none cover, **re-scope the use case** (back to `kata-pov-scope-define`) — do not attempt custom.

### Step 3: Refuse out-of-scope tooling

Vetoed in PoV:

- Custom MCP servers (official MCP servers listed in `.ahrena/.directives::mcp.servers` are OK — Anthropic authorship is not required, as long as they are declared and respect `lex-mcp` Rule 5 on transport preference order)
- Trained ML libraries (transformers, scikit-learn) — stays for `warrior-apollo-agents` (plan-013) when Mêtis designs production
- Integration with a **paid** external API without a public sandbox
- Persistent cross-session cache — Directive 02 in PoV is short-term only

If the primary use case **requires** something from the vetoed list, it is a strong signal that the PoV is premature: document the gap in `pov.md::Out of scope` and proceed without the tool.

### Step 4: Document minimum parameters and examples

For each selected tool, document:

- Operation (verb + object)
- Minimum required parameters
- Real invocation example (not fictional)
- Limit (e.g., "web_search ≤ 3 calls per turn")

### Step 5: Persist tools.md

Write `docs/{context}/agents-pov/{agent}/tools.md` with sections: Required capabilities, Capability→tool mapping, Selected tools (one section per tool), Refused tools (with justification), Per-turn limits.

### Final Validation

- [ ] Every primary-use-case capability has a mapped tool
- [ ] Zero custom MCP
- [ ] Zero ML library
- [ ] Real invocation examples (not invented)
- [ ] Per-turn limits declared

## Outputs

| Output | Format | Destination |
|--------|--------|-------------|
| `tools.md` | Markdown | `docs/{context}/agents-pov/{agent}/tools.md` |

## Execution Example

### Input (pov.md, excerpt)

```
Primary use case: suggest bank-statement-to-ledger-entry pairing by value + date + description.
```

### Output (tools.md, excerpt)

```markdown
## Required capabilities

1. Read bank statement (CSV/OFX) from the project
2. Read ledger entries (CSV exported from the ERP)
3. Run comparison logic (string similarity)

## Capability → tool mapping

| Capability | Anthropic tool |
|---|---|
| Read statement + entries | str_replace_editor (read) |
| Run similarity | code execution (Python sandbox) |

## Selected tools

### str_replace_editor (read)

- Operation: file read
- Minimum parameters: `command=view, path=<file>`
- Example: read of `inputs/statement-2026-04.csv`
- Limit: ≤ 5 reads per turn

### code execution (Python sandbox)

- Operation: run string comparison
- Parameters: `code=<python>`, with `rapidfuzz` allowed as a lightweight dependency
- Example: `compare("Rent payment", "RENT REF MAR/26") -> 0.82`
- Limit: ≤ 1 execution per turn (expensive)

## Refused tools

- Custom MCP for ERP: gap declared in pov.md::Out of scope
- Trained NER model: premature for PoV
```

## Restrictions

- **Never** introduce custom MCP in PoV. If needed, it signals the use case has already moved past the pre-operational stage.
- **Never** declare a tool without a real invocation example.
- **Never** more than 3 tools per PoV. More than that signals a scope that is too broad.

---

**Model:** This Kata applies Directive 03 (`lex-agent-construction-directives`) at pre-operational rigor. Sophisticated tooling stays for Mêtis (plan-032) when the agent is promoted.