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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the bar is lower and 'Read only' merely restates them. Beyond that, the description adds genuinely new operational context: calls consume no Adrails credits and results (reports/questions) come back as structured content rather than prose.

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 first sentence front-loads purpose, scope and the read-before-use instruction with no filler. The trailing MCP/credit sentence is generic boilerplate that is not specific to this tool, which costs it a point but does not bury the essential information.

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?

There is no output schema, and the description compensates by saying the result is a full enumeration of settings each with allowed values and format, so an agent knows what comes back. The main omission is guidance on the no-argument invocation shape and on how a large result set is returned.

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?

Schema description coverage is 75% and the three named parameters (accountIds, userStatement, idempotencyKey) are documented in the schema itself, so the baseline applies. The description says nothing about the required empty 'input' object, which is the only genuinely ambiguous part of the schema; noting 'takes no arguments' would have been the value-add.

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?

States a specific verb and resource ('Returns every setting of the Meta campaign editor') plus the exact scope ('that launch_brief's metaSettings accepts') and the payload each entry carries (allowed values and format). An agent can distinguish this reference lookup from launch_brief and targeting_options without opening any schema.

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?

'Read it before passing metaSettings' gives an explicit ordering trigger tied to a named sibling tool, which is clear usage context. It stops short of stating when the reference is not needed (e.g. if metaSettings is unused) or what to do if a requested setting is absent.

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