Read the current FPS cap (sUNC getfpscap)

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

Annotations cover the safety profile (readOnly/idempotent/non-destructive), yet the description adds substantive behavior beyond them: the call is type-guarded and pcall-wrapped, the exact failure shape ({ error = 'getfpscap is not available...' }), the return shape ({ fpsCap } or { error }), and a cost=medium hint. This is unusually rich disclosure for a read tool.

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?

Front-loaded and information-dense, with the return contract stated early. It is somewhat over-stuffed with template-style metadata ('Phase: observe; cost=medium; idempotency=read-only') and a trailing 'inspect tool-schema' pointer that is meta rather than descriptive, but nothing is seriously wasted.

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 no output schema, the description carries the return contract itself (the numeric cap, 0 = uncapped, or an error object) and names the required runtime capability and active-client precondition. An agent has everything needed to invoke and interpret 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?

Schema description coverage is 100% and both parameters (threadContext, timeoutMs) are already documented in the schema. The description only restates the signature ('{ threadContext: number?, timeoutMs: number? }') without adding format, default, or interaction semantics, so the baseline 3 applies.

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 (read) and resource (render frame-rate cap via getfpscap()), and clarifies the return semantics ('Returns the cap as a number; 0 means uncapped'). It is immediately distinguishable from its obvious sibling set-fps-cap.

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 supplies prerequisites ('Requires getfpscap', 'Requires: active-client') and a phase label ('observe'), which implies when it fits. But it never names alternatives (e.g., set-fps-cap or get-render-stats) or states an explicit when-to-use/when-not condition, leaving routing to inference.

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