cantrip_meter_history

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

With no annotations provided, the description carries full burden. It discloses that this is a read operation ('View'), implies it returns historical data ('recent', 'history'), and mentions filesystem constraints for the project parameter. However, it doesn't specify pagination behavior, rate limits, authentication requirements, or error conditions, leaving some behavioral aspects unclear.

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 efficiently structured in two sentences: the first states the core purpose and data included, the second provides specific usage guidance for the optional parameter. Every sentence adds value with zero wasted words, and it's appropriately front-loaded with the main functionality.

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 read-only tool with 2 parameters (both well-documented in schema) and no output schema, the description provides good context about what data is returned and when to use the optional parameter. However, without annotations or output schema, it could better explain the return format (e.g., structure of transactions, balance presentation) and any limitations (e.g., how 'recent' is defined).

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%, so the schema already fully documents both parameters. The description adds marginal value by explaining the 'project' parameter's purpose ('override .cantrip.json') and when it's useful ('cloud-hosted or multi-project contexts'), but doesn't provide additional syntax or format details beyond what the schema provides. Baseline 3 is appropriate when schema does the heavy lifting.

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 specific action ('View recent credit transactions') and resource ('credit transactions'), distinguishing it from siblings like cantrip_meter_balance (which likely shows current balance only) and cantrip_history (which might be more general). It specifies what data is included: 'usage debits, purchases, and running balance'.

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 explicitly provides when-to-use guidance: 'Pass `project` to override `.cantrip.json` — useful in cloud-hosted or multi-project contexts.' This gives clear context for using the optional parameter versus relying on default configuration, addressing a specific use case scenario.

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