estimate_token_cost

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

With no annotations, the description carries the full burden and does so well: it declares read-only status ('does NOT invoke provider APIs or incur financial billing'), idempotency, and 100% offline operation with local pricing tables. It also states the return shape (a Markdown comparison table) and the $0 Ollama case, covering the safety and behavior profile an agent needs.

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 with the core purpose, then cleanly sectioned into Behavior, Usage Guidelines, and Returns. The labeled sections make it easy to scan, though the multi-line formatting is slightly heavier than strictly necessary for a three-parameter tool.

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 tool with no annotations, this covers everything needed: what it computes, that it is offline/safe/non-billing, when to use it, the sibling alternative, and a brief note on returns (output schema exists, so return detail is not required). Nothing an agent needs to call it correctly is missing.

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 documents all three parameters, giving a baseline of 3. The description adds only a light gloss ('for a given text or directory') and does not explain reduction_mode ('ultra', 'balanced', 'none') beyond what the schema already provides.

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+resource ('Calculates exact token count and estimated API prompting cost') and scopes it to named providers (OpenAI GPT-4o, Claude 3.7 Sonnet, Groq, NVIDIA NIM, Ollama). It also distinguishes itself from the sibling get_token_savings_metrics, so an agent can route without opening either schema.

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?

Includes an explicit 'When to use' condition (estimating prompt/cost before sending large codebase context to commercial APIs) and an explicit 'Sibling Routing' exclusion pointing to get_token_savings_metrics for cumulative ROI tracking. Both the trigger and the alternative are named directly.

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