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

The description clearly states 'read-only' and explains the data provenance (project id, serial, vintage) and cross-referencing capability. However, with no annotations provided, it fails to disclose other behavioral traits such as rate limits, authentication requirements, or response size constraints. The retirement economics (85/15 split) is market context, not tool behavior. An output schema exists, so return structure is covered, but additional behavioral context is minimal.

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 three sentences long, starting with the core concept (the book). It front-loads the key information. The final sentence about retirement economics is tangential to the tool's operation but adds context without excessive bloat. Could be slightly tighter by merging the first two sentences, but overall concise.

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?

Given no parameters and an existing output schema, the description provides adequate context about the data source (Verra VCS book) and read-only nature. However, it does not clarify how this tool differs from similar list/query tools (e.g., list_credit) or what 'supply' means in the tool name. The completeness is adequate but has notable gaps in purpose and usage differentiation.

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?

There are zero parameters, and the schema description coverage is 100%. The baseline for 0 parameters is 4, and the description does not need to add parameter information. It meets this baseline adequately.

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 uses a noun phrase ('the tradeable Verra VCS book') rather than a verb, failing to explicitly state what action the tool performs. It implies a read/list operation via 'read-only' but does not specify the core function (e.g., query, view, list). This vagueness makes it hard for an agent to distinguish from sibling tools like list_credit or net_position.

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?

No guidance is provided on when to use this tool versus alternatives. The description mentions 'read-only' but does not contrast with write tools (like buy_offset) or other query tools (like list_credit, net_position). There is no explicit when-to-use or when-not-to-use advice.

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