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

The annotations already establish a non-destructive read, and the description adds useful output behavior by naming the three measures and their cents unit. It does not clarify snapshot timing, handling of unknown or expired sessions, or representation of sessions without a cap.

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?

A single front-loaded sentence conveys the operation, scope, returned fields, and units without filler. The slash-separated phrasing is compact but remains understandable.

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 one-parameter read, the definition is sufficient to infer the basic call and expected budget information. With no output schema, however, it remains thin about response shape and edge cases, and it lacks session-ID acquisition and alternative-tool guidance.

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 sole parameter has no schema description, and the description only indirectly supports it through the phrase 'for an agent session.' It does not document the expected identifier format, validity requirements, or where to obtain agent_session_id.

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 gives a clear verb, resource, and scope, and specifies the returned values: spent, cap, and remaining cents for an agent session. It does not explicitly distinguish this session-level view from siblings such as merjax_ai_cost_summary or merjax_list_token_spend.

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 agent-session scope implies using the tool to check one session's budget, but there is no explicit when-to-use or when-not guidance. It also does not direct agents to aggregate cost or token-spend alternatives when those are more appropriate.

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