ContextFetch balance

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

Annotations already declare readOnlyHint and openWorldHint, so the bar is lower; the description still adds real context by noting the required CONTEXTFETCH_API_KEY env var, that the call is free, and that a failed payment surfaces a last auto-reload error. It does not describe the response shape, which is a minor gap given no output schema.

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?

Two dense sentences, front-loaded with what is returned, then the auth/cost constraint and usage trigger. No filler or repetition of the name.

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 zero-parameter read tool with no output schema, the description covers auth requirements, cost, what data is returned, and when to call it — everything an agent needs to invoke it correctly.

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 tool takes zero parameters, so the baseline is 4; the description correctly does not invent parameters and instead clarifies the implicit auth dependency (CONTEXTFETCH_API_KEY).

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 (Show) and a precisely enumerated resource: remaining credits, 7-day burn rate, and auto-reload settings. This is clearly distinguishable from siblings like contextfetch_auto_reload (which would modify settings) and contextfetch_search.

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?

Gives a concrete trigger — 'Check it before long jobs' — and signals it is free, implying no credit cost for polling. It does not explicitly name an alternative or a when-not condition, so it falls short of a 5.

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