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

Annotations already indicate readOnlyHint, openWorldHint, and idempotentHint, so the tool is known to be safe and non-mutating. The description adds behavioral context such as the 'ok is false' condition meaning no passage found, and the dual-layer search behavior, which goes beyond annotations.

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 verbose and dense, with a long list of sources that could be in the enum or a separate document. It lacks front-loading of the core purpose; a lot of detail is packed into one paragraph, making it hard to parse quickly.

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?

The description is rich with context for a complex tool: it explains the data sources, layers, and the 'ok' flag. Although there's no output schema, the description covers return behavior (e.g., cited passages, 'ok is false'), which is sufficient for an agent to use 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?

Schema description coverage is 100%, so the schema already documents each parameter adequately. The description adds some semantic context around 'source' (e.g., 'price' for CoinMetrics price) and the meaning of 'when' (date pinning), but mostly reiterates schema info, so a baseline 3 is appropriate.

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 identifies the tool as a search over a cited Bitcoin coordination index, with a specific resource (index) and a clear scope. It distinguishes itself from siblings by focusing on the index search rather than analysis or retrieval of specific passages, though it does not explicitly name sibling tools.

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 provides explicit guidance on when to use the tool: it's not a live quote, ETF, or derivatives, and it explains how to pin a layer with source. It implies that the tool covers both layers of search, but it doesn't contrast with alternatives like 'get_passage' or 'find_discourse' explicitly.

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