# Tool Exists but Required Inputs Are Missing

## Ontology Metadata

Code: ISS-0020
Version: ISS-0020@0.1.0
Ontology release: 0.1.0
Updated: 2026-05-10T00:00:00Z
Canonical URL: /workbench/issues/tool-exists-but-required-inputs-are-missing/

## Summary

A usable tool or integration exists, but the AI or agent does not have the required inputs, permissions, fields, identifiers, or context needed to call it correctly.

## Category

- CAT-0040 — MCP, Tools & Integrations
  - URL: /workbench/categories/mcp-tools-and-integrations/
  - Summary: Problems involving tool calls, MCP surfaces, integration contracts, required tool inputs, tool results, parser consumers, or downstream systems that depend on AI output.

## Primary Pattern

- PAT-0130 — Incomplete Declaration
  - URL: /workbench/patterns/incomplete-declaration/
  - Summary: A structural condition where an element is declared but required attributes, dependencies, or linked definitions are missing.

## Declared Patterns

- PAT-0130 — Incomplete Declaration
  - URL: /workbench/patterns/incomplete-declaration/
  - Summary: A structural condition where an element is declared but required attributes, dependencies, or linked definitions are missing.
- PAT-0170 — Constraints Underspecified
  - URL: /workbench/patterns/constraints-underspecified/
  - Summary: A structural condition where declared constraints are insufficient to eliminate ambiguity or multiple admissible states.
- PAT-0150 — Interface Mismatch
  - URL: /workbench/patterns/interface-mismatch/
  - Summary: A structural condition where observed interface behavior, shape, or exchange differs from the declared interface contract.

## Derived Primary Lenses

- LEN-0100 — Absence Lens
  - URL: /workbench/lenses/absence-lens/
  - Summary: Detects structurally required elements that are missing from the observed structure.
- LEN-0160 — Constraint Sufficiency Lens
  - URL: /workbench/lenses/constraint-sufficiency-lens/
  - Summary: Evaluates whether declared constraints are sufficient to eliminate structural degrees of freedom.
- LEN-0200 — Interface Contract Lens
  - URL: /workbench/lenses/interface-contract-lens/
  - Summary: Compares declared interface structure to observed runtime structure to detect contract deviations.

## Derived Secondary Lenses

- LEN-0180 — Determinism Lens
  - URL: /workbench/lenses/determinism-lens/
  - Summary: Evaluates whether identical structural inputs produce equivalent structural outputs across repeated executions.
- LEN-0230 — Normalization Lens
  - URL: /workbench/lenses/normalization-lens/
  - Summary: Transforms structurally equivalent variants into a canonical form to prevent false divergence.
- LEN-0290 — Variance / Entropy Lens
  - URL: /workbench/lenses/variance-entropy-lens/
  - Summary: Measures structural variability across repeated or comparable evaluations and identifies divergence beyond expected bounds.

## Search Intents

- tool exists but required inputs are missing
- AI cannot call tool missing inputs
- agent needs required tool fields
- tool available but not enough information
- missing inputs for MCP tool
- AI tool call lacks required parameters