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

With no annotations provided, the description carries the burden of behavioral disclosure. It states 'found, verbatim WEB text, never generated', which conveys reading sourced content rather than generating new text. It also explains the behavior based on the presence or absence of the id parameter. This is informative, though it could mention return format or error cases.

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 just two sentences, front-loaded with the core purpose. The parenthetical 'found, verbatim WEB text, never generated' adds important trust context without padding. The second sentence efficiently covers parameter usage and default behavior. No unnecessary words.

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 one optional parameter and no output schema, the description covers purpose, behavior, and parameter semantics. It gives a clear expectation of what is returned ('side by side' and 'grouped by phase'). It lacks details on event ID structure or output format, but these are secondary given the tool's simplicity.

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 schema only defines 'id' with type and maxLength, but the description explains that 'id' selects a single event and is optional, with default behavior of listing all events. This adds meaningful context beyond the bare schema. It does not specify id format or source, but the description compensates for the 0% schema coverage.

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 specifies a clear verb and resource: 'Harmony of the Gospels' — showing parallel gospel accounts of a single event. It distinguishes itself from sibling tools like read_passage or commentary by focusing on side-by-side comparison. The addition of 'Pass id for one event; else lists every event grouped by phase' further clarifies the tool's exact scope and capabilities.

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 gives explicit usage guidance: pass an id to retrieve one event, or omit it to receive all events grouped by ministry phase. While no alternatives are named, the context makes when to use this tool clear. It lacks explicit statements about when not to use it, but the guidance is sufficient for basic use.

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