- Updated
- Version
- v1.7
- Sources
- 5 sources
- Status
- Published
tool call
Tool
A callable operation that lets an agent observe or change a system through an input and output contract.
Everyday phrases
- an external capability the agent calls
- delegating an action to a tool
Key difference
A tool provides a capability; a skill explains when and how to use it in a procedure.
Example
A function reads a file and returns its content with an explicit error status.
Counter-example
A review checklist is not an executable tool; it may be part of a skill.
Continue with a guide
Related concepts
Sources
- https://modelcontextprotocol.io/specification/2025-06-18/server/tools
- https://platform.claude.com/docs/en/agents-and-tools/tool-use/how-tool-use-works
- https://openai.github.io/openai-agents-python/tools/
- https://cdn.openai.com/business-guides-and-resources/a-practical-guide-to-building-agents.pdf
- https://agentskills.io/specification
Revision glossary-v1.7:tool · 2026-08-03
- Sourced content digest
- sha256:a3fd91577a302212375379ae22ee8726b57bc1bd15a519970a646222aa36d49c
Understand → Recognize → Choose → Compare
Pack for your agent
Pre-written instruction by SkillCodex — your request is neither sent nor used to adapt this text; no content is generated, and copying executes nothing.
Implement correctly
Use Tool deliberately
# Ground Tool in your agent ## Objective Use “Tool” precisely in code, documentation, and conversations: A callable operation that lets an agent observe or change a system through an input and output contract. ## Prerequisites - Inspect how the term is used today in the repository, documentation, and prompts. - Identify the neighboring notions already named: Skill, Agent, Model Context Protocol (MCP). - Preserve existing correct usages. ## Working definition A callable operation that lets an agent observe or change a system through an input and output contract. ## Decisive difference A tool provides a capability; a skill explains when and how to use it in a procedure. ## Example that counts as Tool A function reads a file and returns its content with an explicit error status. ## Counter-example A review checklist is not an executable tool; it may be part of a skill. ## Acceptance criteria - Every use of the term matches the working definition. - Edge cases are settled with the decisive difference, not by intuition. - Neighboring notions (Skill, Agent, Model Context Protocol (MCP)) are named with their own term. ## Guardrails - Show the proposed changes before any external action. - Do not publish, send, delete, pay for, or change remote state without explicit authorization. - Preserve unrelated changes and stop if the scope becomes ambiguous. ## Output format - Outcome or verdict. - Files or actions involved. - Checks run and observable evidence. - Remaining blockers or limitations.
- Requires · The agentic vocabulary already used in the repository and documentation
Why it works
- The notion is framed by a sourced working definition, not ambient usage.
- The decisive difference settles edge cases reproducibly.
- The example and counter-example bound the term on both sides.
Try next
Map the neighboring notions
# Map the neighboring notions ## Objective Extend the same rigor to the related notions (Skill, Agent, Model Context Protocol (MCP)) so the project vocabulary stays coherent. ## Checks - List every neighboring notion used without a definition. - Apply its documented decisive difference. - Record the still-ambiguous cases for the next entry. ## Guardrails - Show the proposed changes before any external action. - Do not publish, send, delete, pay for, or change remote state without explicit authorization. - Preserve unrelated changes and stop if the scope becomes ambiguous. ## Output format - Outcome or verdict. - Files or actions involved. - Checks run and observable evidence. - Remaining blockers or limitations.
sha256:f7cba79247f4151b73b6b281bba7948577baeddbfae9e085caaa7054d60c9ae0
Diagnose a problem
Fix a Tool mix-up
# Fix a mix-up around Tool ## Observed symptom [DESCRIBE THE SYMPTOM HERE] ## Observable checks - Compare the disputed usage with the working definition: A callable operation that lets an agent observe or change a system through an input and output contract. - Apply the decisive difference: A tool provides a capability; a skill explains when and how to use it in a procedure. - Confront the case with the documented counter-example: A review checklist is not an executable tool; it may be part of a skill. ## Possible causes - The term is used for a neighboring notion (Skill, Agent, Model Context Protocol (MCP)). - The observed form (interface, script, service) is confused with the actual behavior. - An alias (tool call) carries a different meaning in the project. ## Bounded fixes - Rename or reclassify only the usages that contradict the working definition. - Document each choice by citing the decisive difference. ## Final verification - Reread every corrected occurrence against the documented example and counter-example. ## Guardrails - Show the proposed changes before any external action. - Do not publish, send, delete, pay for, or change remote state without explicit authorization. - Preserve unrelated changes and stop if the scope becomes ambiguous. ## Output format - Outcome or verdict. - Files or actions involved. - Checks run and observable evidence. - Remaining blockers or limitations.
- Requires · The agentic vocabulary already used in the repository and documentation
Why it works
- The diagnosis compares usage with documented criteria instead of an opinion.
- Fixes stay bounded to genuinely contradictory usages.
- The final verification runs back through the sourced example and counter-example.
Try next
Anchor the vocabulary in the project
# Anchor the vocabulary in the project ## Objective Turn the clarification into a reusable rule so the mix-up does not return. ## Checks - Add the working definition to the project glossary. - Link every neighboring term to its own entry. - Check new documents against the decisive difference. ## Guardrails - Show the proposed changes before any external action. - Do not publish, send, delete, pay for, or change remote state without explicit authorization. - Preserve unrelated changes and stop if the scope becomes ambiguous. ## Output format - Outcome or verdict. - Files or actions involved. - Checks run and observable evidence. - Remaining blockers or limitations.
sha256:c80377c85c389d8b6b45276f8a59ad0be5b68f3f6ee68b64592cc6c89bb57ce8
Pack digest: sha256:b0655edac6b79f0795f7313abd80c038da77d25db4865184b8ff00e19025b34d