spend_status

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

No annotations exist, so the description carries the full behavioral burden. It does add genuine value by clarifying the cap is local to this MCP server (not an on-chain balance) and that it reports authorised-so-far vs. remaining, but it never states that the call itself is free/read-only, nor any permission or freshness caveats.

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 sentences, zero filler, with the identity of the resource front-loaded and the usage cue placed second. Every clause earns its place.

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?

With no output schema, the description correctly compensates by naming the three returned values (cap, authorised, remaining). It is close to complete for a trivial no-arg tool, though it omits units/currency and any indication of whether the reading can be stale.

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 and there is nothing for the description to disambiguate beyond the absence of inputs.

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?

Specific verb ("Show") plus a precisely scoped resource ("this MCP server's local x402 spend cap"), and it enumerates the three values returned. None of the siblings (weather, earthquakes, iss, etc.) overlap, so there is no ambiguity about which tool handles spend status.

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?

Explicitly states the triggering context: "Use it to decide before calling a paid tool." That is clear when-to-use guidance, though it does not name which sibling tools are the paid ones or state any exclusion, so it falls short of a full routing rule.

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