What a Page is subscribed to

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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds critical behavioral context: it reads straight back from Meta rather than from stored data, states it is read-only and costs 0 credits, and warns that an unsubscribed Page is completely silent and indistinguishable from a quiet one. This goes well beyond the annotation hints and provides the agent with reasoning to avoid false conclusions.

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

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

The description is a well-structured paragraph that front-loads the core function ('What Meta ACTUALLY has recorded'), then delivers a critical usage warning, and closes with a cost note. Every sentence earns its place; there is no fluff or redundancy. It is long enough to be informative but not verbose, and the urgent 'CHECK THIS' phrase is placed immediately after the purpose for high salience.

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

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

For a simple read-only status tool with one optional parameter and no output schema, this description is complete. It explains what the tool returns (the subscription fields), when to use it (before diagnosing webhook issues), and the behavioral caveat about silent pages. Nothing an agent needs to invoke it correctly is missing.

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

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

The schema has 100% description coverage for the single optional parameter 'pageId', fully documenting it. The description does not add any additional semantic detail about the parameter beyond what the schema provides. Since the schema carries the load, a baseline of 3 is appropriate.

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

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

The description states the precise function: reading what Meta has actually recorded for the app on a Page — the fields it will push, retrieved directly from Meta. It clearly distinguishes itself from sibling tools like subscribe_meta_webhooks or unsubscribe_meta_webhooks by emphasizing the read-back aspect, and from list_meta_webhook_events by focusing on subscription state rather than events. The purpose is unambiguous and actionable.

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

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

The description explicitly says 'CHECK THIS BEFORE CONCLUDING THAT WEBHOOKS ARE NOT WORKING' and explains that an empty event feed is not evidence until the subscription is confirmed. This provides a clear when-to-use rule and a diagnostic rationale. It doesn't explicitly name alternative tools, but the guidance strongly routes the agent to this tool first in troubleshooting scenarios. It also notes '0 credits', a financial consideration.

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