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

Annotations already declare readOnlyHint=true and openWorldHint=true, indicating safe read-only and potentially variable results. The description adds value by revealing the internal dependency on a 'spendtron connection' and that authentication is via API key, which is useful behavioral context. It does not detail what happens if no connection exists, but given annotation coverage is decent, this is acceptable. No contradiction exists.

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 a single sentence that is front-loaded with the main purpose ('Ranks... by real compute cost') and efficiently packs in the key context: the resource scope, the methodology, and the absence of arguments. Every part of the sentence earns its place, with no filler or redundancy.

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 parameters and a clear read-only audit purpose, the description covers the essential information: what it does and that it requires no arguments. It notably does not describe the return format or the behavior when the spendtron connection is unavailable, but since there is no output schema and annotations provide some safety context, the description is nearly complete. A small extra sentence on potential results would make it a 5.

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 has zero parameters, so the schema is trivially complete (100% coverage). The description reinforces that no arguments are needed, which is helpful for an agent. Since there are no parameters to explain, a baseline of 4 is appropriate, and the description adds clarity by stating the lack of parameters.

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 tool's purpose: 'Ranks your GitHub org's Actions workflows and repos by real compute cost.' It identifies the resource (GitHub org's Actions workflows and repos), the specific action (ranks by compute cost), and the methodology (using spendtron connection). There are no siblings, so no differentiation is needed, and the description is unambiguous.

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 states the tool requires no arguments ('no arguments needed') and that the account is identified by the API key. This makes it clear when to use it: whenever an audit of Actions cost is needed. There is no mention of when not to use it, but with no siblings and a self-contained tool, that absence is not a significant gap. The context (audit, cost) is clear enough.

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