D365 F&O MCP Server

extension_info

Read-only

Analyze D365 F&O code for extensibility conflicts and recommend the correct customization method—Chain of Command, events, table merge, or an alternative approach.

Instructions

D365FO extensibility analyzer. Choose a mode: • coc → Chain of Command extensions + event subscriptions for a class/table. Use before writing a CoC extension to check for conflicts. • events → event handler subscriptions (SubscribesTo, delegate +=) for a class/table. Use before adding handlers to check for duplicates. • table-merge → all extensions of a table across models + effective merged schema (base + extension fields/indexes/methods). • points → available extension points (CoC-eligible/replaceable methods, delegates, blocked methods) and which are already extended. • strategy → recommends the best extensibility mechanism for a goal (CoC, event handler, business event, data entity, …) with reasoning, risks, alternatives, next steps.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`goal`	No	[strategy] REQUIRED. What you want to achieve — e.g. "validate that SalesLine quantity is positive".
`mode`	Yes	coc/events/table-merge/points need `target`; strategy needs `goal`.
`method`	No	[coc] filter to a specific method name; [events] filter to a specific event name (e.g. onInserted).
`target`	No	The base object: [coc] class/table being extended; [events] class/table whose handlers to find; [table-merge] base table; [points] class/table/form; [strategy] optional target object.
`scenario`	No	[strategy] Scenario category (auto-detected from goal if omitted). field-defaulting = set defaults on NEW records (initValue); field-change-reaction = react when a user/code CHANGES a field (modifiedField).
`objectType`	No	[events] set "table" when target is a table (else class is assumed); [points] object type (default: auto-detect).	auto
`handlerType`	No	[events] Filter by handler type (default: all).	all
`includeEventHandlers`	No	[coc] Also find static event subscriptions (SubscribesTo) (default: true).
`includeEffectiveSchema`	No	[table-merge] Merge base + extension counts (default: true).
`showExistingExtensions`	No	[points] Also list who already wraps/subscribes each point — opt-in, roughly doubles the response.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv1.14.0Aug 25, 2026

changedInput schema / properties / showExistingExtensions / default
```
Previous value: -trueNew value: +false
```

changedInput schema / properties / showExistingExtensions / description

Previous value: -"[points] Show which extension points are already extended (default: true)."New value: +"[points] Also list who already wraps/subscribes each point — opt-in, roughly doubles the response."

First observedv1.8.0Aug 4, 2026

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnlyHint=true and openWorldHint=false, so the tool is known to be read-only. The description adds behavioral context by detailing what each mode returns or analyzes (e.g., effective merged schema, available extension points, who already wraps). It also notes that showExistingExtensions 'roughly doubles the response', a practical performance trait. It does not contradict annotations and adds value beyond them, though it doesn't cover potential errors or latency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a compact bulleted list, front-loaded with a clear one-line purpose. Each mode is described in one or two sentences with no redundancy. The structure is scannable and every sentence earns its place, from the overall analysis purpose to mode-specific guidance.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 10 parameters and 5 modes, the description covers all modes and their intended use cases, including which parameters are relevant per mode. It explains outputs (e.g., merged schema, extension points, recommendations) sufficiently without an output schema. No missing critical information prevents an agent from calling the tool correctly, making it complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% with detailed per-parameter descriptions (e.g., mode: 'coc/events/table-merge/points need target; strategy needs goal'). The description adds mode-level context but does not introduce new parameter meanings beyond the schema. Since the schema already documents parameters thoroughly, the baseline of 3 is appropriate; the description names which modes use which parameters, slightly aiding selection but not adding substantial semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states 'D365FO extensibility analyzer' and enumerates five distinct modes (coc, events, table-merge, points, strategy) with specific resources and goals. Each mode is tied to a concrete action (e.g., 'Chain of Command extensions + event subscriptions for a class/table'), making it unambiguous what the tool does and how it differs from generic search or analysis tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Every mode includes explicit usage context: 'Use before writing a CoC extension to check for conflicts', 'Use before adding handlers to check for duplicates'. The strategy mode states it 'recommends the best extensibility mechanism for a goal', and the description explains which parameters each mode requires. This provides clear when-to-use guidance for each variation, effectively distinguishing from siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

extension_info

Instructions

Input Schema

Schema Changelog

TDQS

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