Facebook Ad Library MCP

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list_advertisers

Read-onlyIdempotent

Resolve a brand name to advertiser Pages running ads for it, ranked by ad volume. Use when you know the brand but not its Page ID, then pass the ID to search_ads.

Instructions

Resolve a brand name to the advertiser Pages actually running ads for it, ranked by how many ads each is running. Use this first when you know the brand but not its Page ID, then pass that ID to search_ads to get everything they run.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`query`	Yes	Brand or company name to look up.
`country`	No	Two-letter country code. Default US.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`note`	No
`count`	Yes
`advertisers`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv0.6.1Oct 6, 2026
- removedInput schema / $schema
```
Removed value: -"http://json-schema.org/draft-07/schema#"
```
- removedInput schema / additionalProperties
```
Removed value: -false
```
- removedOutput schema / $schema
```
Removed value: -"http://json-schema.org/draft-07/schema#"
```
First observedv0.4.0Sep 1, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavior beyond that: results are ranked by ad volume, and the tool performs fuzzy brand-name resolution rather than exact lookup. It does not mention result limits or ambiguity handling, so it stops short of a 5.

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?

Two sentences, no waste, front-loaded with the core purpose and followed by the workflow handoff. Every clause earns its place.

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?

With an output schema present, the description needn't explain return values, and it covers purpose, ranking, and the chaining workflow to search_ads. Nothing an agent needs to select or invoke this tool correctly is missing.

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 coverage is 100%, so both parameters are already documented, and the description adds no syntax or format detail for them. It clarifies the intent of the query (brand-name resolution) but says nothing about the country parameter, so the baseline 3 applies.

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?

States a specific verb (resolve) and resource (brand name → advertiser Pages), plus the ranking behavior. It is clearly distinguishable from search_ads and the other siblings, which retrieve ads rather than resolve brand names to Page IDs.

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?

Explicitly says to use this first when you know the brand but not its Page ID, and names the downstream alternative (search_ads) plus the handoff artifact (the ID). This is a complete when/when-not routing instruction.

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

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