CONTRACT DESK / COMPARE03 NOTES
Same idea.
Different rules.
Field-level differences that change client code, not marketing feature tables.
What this section covers
“It supports function calling” is where the similarity ends. The wrapper key differs, strictness differs, the accepted JSON Schema subset differs, and the way each provider expresses an optional parameter differs enough to change how a model interprets the tool.
These comparisons record the specific fields that force a code change, and cite the provider documentation behind each row so a production decision can be rechecked against the version you have pinned.
Provider schema comparisons
OpenAI vs Anthropic tool schemas: strict-mode differences
Compare wrappers, required fields, optionality, object closure, and complexity limits for OpenAI and Anthropic strict tools.
- parameters vs input_schema
- Required-field semantics
- Complexity ceilings
OpenAI vs Gemini function calling schema differences
Compare strictness, supported schema subsets, nullable fields, and active-tool design for OpenAI and Gemini.
- Similar wrapper, different subset
- Strict required semantics
- Gemini tool-set sizing
MCP 2025-11-25 vs 2026 tool schema changes
Understand JSON Schema 2020-12 support, root rules, and output schema changes in the MCP 2026 release candidate.
- Full JSON Schema 2020-12
- Input root remains object
- Unrestricted output schema
RELATED WORKBENCHES01
Reproduce it locally.
These tools take the same evidence the notes above describe and compute the result in your browser tab.
Section FAQ
Before you dig in
Do these pages rank providers?
No. They record wire-level differences. Which trade-off is correct depends on the tools you ship and the models you route to.
How current are the comparisons?
Each note names its primary source and review date. Tool-calling surfaces change frequently, so verify against your pinned API or protocol version before deploying.
CONTINUERELATED SECTIONS
Provider validators report a symptom at the root. The defect is usually several nodes deeper.
Open section →Contract deskTool schema convertersMechanical repairs where intent is recoverable; explicit warnings where it is not.
Open section →Workbench indexAll six APITC toolsDecode, simulate, analyse, plan, diff, and compile — locally.
Open section →