session_budget

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

The description fully discloses behavior: it is read-only, does not save tokens, and clarifies that burnFraction measures hook activity not context-window occupancy. No annotations exist to contradict this.

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 extremely concise with only two sentences and a note, each sentence providing essential information without redundancy.

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?

Given the tool is simple with one parameter and no output schema, the description fully explains what it reports (suppressed tokens, reference budget, burn fraction, denyThreshold) and clarifies a common misunderstanding, making it complete.

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 description adds meaning beyond the schema by explaining that sessionId can be empty to read without filter and that it matches hook-events.jsonl ids, which enriches the schema's parameter description.

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 the tool is a diagnostic that reports read-hook pressure for a session, distinguishing it from other tools by labeling it as 'META / info-only' and specifying it does not save tokens.

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 provides explicit guidance on when to use the tool ('use to decide when to tighten before a big read'), but does not explicitly mention alternatives or when not to use it.

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