list_clients

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

No annotations are provided, so the description carries the full burden. It does disclose the return payload (ID, name, platforms), which is useful behavioral context, and 'Lists' implies a non-mutating read. But it says nothing about auth requirements, whether results are paginated, empty-state behavior, or caching/rate limits.

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?

Three sentences, no filler, and the most important detail (call this first to get client_id) is placed at the end as the actionable takeaway after the payload description. Every sentence earns its place.

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 parameterless discovery tool with no output schema, the description fully compensates by enumerating the returned fields and the platform enum values (google_ads, meta_ads, tiktok_ads). An agent has everything needed to call it and consume the result.

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?

With zero parameters, the baseline is 4. The description goes slightly beyond by explaining the meaning of the returned client_id ('used in other tools'), which is the key semantic an agent needs even though it isn't an input.

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 ('Lists all configured accounts available in this MCP server') and immediately clarifies the shape of what an account is (ID, name, platforms). An agent can distinguish it from the many per-platform performance siblings 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?

Explicit routing instruction: 'Call this first when you need to know which client_id to pass to other tools.' That names both the trigger condition and the downstream dependency on sibling tools, which is exactly the guidance needed for a discovery tool.

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