pbi_capabilities

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

With no annotations provided, the description carries the burden of explaining behavior. It discloses that the tool is an introspection/query tool that reports capabilities and reasons, and clarifies that it indicates whether writing is possible, not that it performs writes. It does not detail potential side effects, but the described nature makes side effects unlikely.

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 concise and front-loaded with the core idea. Every sentence adds value: the first states the tool's function, the second provides usage guidance and specific capability areas. There is no redundancy or fluff.

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?

With zero parameters and an output schema present, the description needs only to explain the tool's role and what it reports, which it does thoroughly. It also gives essential context about when to invoke it, making it complete for an agent to decide to call 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 the schema provides no semantic value. The description compensates by explaining what the tool evaluates (live layer, .pbip writability, engine version capabilities), giving the agent enough context to understand the tool's scope without needing parameters.

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 clearly states what the tool does: it reports what can be done 'right now' and what cannot, with the reason. It also gives a specific use case ('an agent should consult it before planning') which distinguishes it from sibling tools like pbi_health_check or pbi_session_info.

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?

It explicitly advises when to use the tool ('before planning') and lists what it checks (live layer availability, write access to .pbip, engine-version-dependent capabilities). It does not mention exclusions or alternatives, but the guidance is clear and actionable.

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