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

With no annotations, the description carries the full burden and does well: it discloses the escalation sequence, that the response reports which tier served it, and full cost mechanics ($0.008 base, 70% cache discount, $0.004 x402 payment floor). It stops short of stating auth mechanics, error/retry behavior, or rate limits, but the cost and latency-relevant context is unusually thorough.

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?

Three sentences, front-loaded with the core behavior before the pricing detail. Each sentence carries distinct information (mechanism, fallback trigger, cost). The pricing sentence is dense but not redundant with the schema's cache description.

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 5-param tool with no annotations and no output schema, the description covers what it does, how it escalates, what the response signals, and what it costs. Remaining gaps (error handling, auth flow, response shape beyond the tier field) are minor but real, so it falls short of fully self-sufficient.

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 all five parameters are already documented, including cache pricing and the Pro-tier restriction on waitFor. The description reinforces the cache discount and tiering but adds no syntax or format detail beyond the schema. Baseline 3 is appropriate when the 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?

States a specific verb+resource ('resilient fetch') and immediately explains the mechanism: native scraper first, headless Chromium fallback. An agent understands it is a scraping fetch with tiered escalation. It does not explicitly name the siblings it overlaps with (fetch_webpage, fetch_webpage_pro, get_contents), so differentiation is left to inference.

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 describes the conditions that trigger the fallback tier (client-rendered pages, sites refusing bare HTTP clients), which implies when this tool is the right pick. However, it never tells the agent when to choose this over fetch_webpage or fetch_webpage_pro, nor when not to use it. Usage is implied rather than directed.

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