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

Beyond the annotations (readOnlyHint=true, idempotentHint=true, etc.), the description adds important behavioral context: the execution_enabled field is authoritative and discovery does not authorize session execution. It also discloses the required auth header. These are critical nuances not conveyed by annotations alone.

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 only two sentences and front-loads the purpose immediately. Each sentence earns its place: the first details what is read, the second adds a critical caveat and the auth requirement. No wasted words.

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 zero-parameter, read-only tool with an output schema, the description is complete: it lists the specific data points returned, clarifies the authoritative field, and states the auth requirement. There is no ambiguity about what the tool does or how to invoke it.

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 tool has zero parameters, so there are no parameter semantics to explain. The schema coverage is 100% vacuously. The description focuses on return data rather than parameters, which is appropriate. A score of 4 reflects the baseline for no-parameter tools.

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 uses a specific verb ('Read') and clearly identifies the resource: the registered parent agent's effective Direct Session limits (concurrency, spend, duration, request, byte) plus platform availability. It distinguishes itself from sibling tools like get_direct_usage and get_capabilities by focusing on limits rather than usage or capabilities.

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 gives clear context: it reads limits and requires an Authorization: Bearer header. It also implies that this is for discovery, not authorization, but it does not explicitly name alternatives or say 'use this instead of X.' Still, the purpose and prerequisites are clear enough for an agent to decide when to call it.

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