Issue
Agent Cannot Choose Tool Without Tool Result
The agent needs a tool result to choose the right tool, but cannot obtain that result without choosing a tool first.
What This Looks Like
The agent needs information from a tool result to decide which tool to call, but it must choose a tool before it can get that information. The workflow may stall, guess, call the wrong tool, ask unnecessary questions, or loop between possible tools without a valid selection rule.
Why It Matters
Tool selection needs enough input to be decidable. When the required evidence depends on the tool choice itself, the agent can become trapped in a circular dependency. This creates unreliable tool use and makes failures look like model indecision rather than a broken selection structure.
Structural Signal
The tool-choice decision depends on information that is only available after the tool-choice decision. The issue is not one bad tool call; it is a circular dependency in the tool selection process.
Common Triggers
- Tool descriptions require knowing the result before selecting the tool
- The workflow lacks a discovery or metadata step
- Multiple tools appear valid until one is called
- Required routing fields can only be generated by downstream tools
- The agent is not allowed to ask for missing selection inputs
- Tool selection rules are described in terms of unavailable state
When to Use This Issue
Use this Issue when an agent cannot choose the correct tool because the information needed to choose is only available after calling a tool.
When Not to Use This Issue
Do not use this Issue when the required tool is available and the agent simply picks the wrong one. Do not use it when the tool exists but required inputs are missing outside a circular selection dependency.
Category
Primary Pattern
Declared Patterns
Circular Dependency
A structural condition where two or more elements depend on each other in a closed loop without an independent base condition or declared resolution mechanism.
Missing Authority
A structural condition where a region, action, state, or decision path exists without a declared governing authority.
Interface Mismatch
A structural condition where observed interface behavior, shape, or exchange differs from the declared interface contract.
Derived Primary Lenses
Absence Lens
Detects structurally required elements that are missing from the observed structure.
Authority Overlay Lens
Maps declared authority hierarchies onto observed structure to detect absence, override, or conflict.
Conflict Lens
Detects mutually incompatible constraints, claims, states, or declarations that cannot be simultaneously satisfied.
Interface Contract Lens
Compares declared interface structure to observed runtime structure to detect contract deviations.
Propagation Lens
Traces how structural declarations, effects, or state changes propagate across boundaries or stages.
Derived Secondary Lenses
Related AI-Adjacent Issues
Search Intents
- agent cannot choose tool without tool result
- AI needs tool result to pick tool
- tool choice circular dependency
- agent stuck choosing tool
- AI cannot decide tool without data
- MCP tool selection loop