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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds valuable behavioral context beyond that: it handles prefixes/inflected forms and uses context_ref for disambiguation. This tells an agent how the tool behaves, not just what it is.

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 tight sentences, no filler. The primary action and scope are front-loaded, followed by useful behavioral and disambiguation guidance. Every sentence 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?

For a read-only lookup tool with seven parameters, the description plus schema cover the essentials: required word, dictionary selection, context_ref usage, and split behavior. It lacks an explicit note about return shape, but there is no output schema and the read-only annotations reduce the need for safety caveats. A small gap remains in not pointing to dictionary_autocomplete when the user only wants suggestions.

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 71%, so the schema carries most parameter meaning. The description compensates for at least one gap: it explains context_ref as a disambiguation aid using the passage, and 'Handles prefixes/inflected forms' gives purpose to the splitting-related parameters. It does not cover always_split explicitly, but the description still adds real semantic value beyond the schema.

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 opens with a specific verb and resource: 'Look up a Hebrew or Aramaic word in classic dictionaries (Jastrow, BDB, Klein, and others).' This clearly distinguishes the tool from browsing texts, calendar tools, or library search, and it names concrete dictionaries that make the scope unmistakable.

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 one actionable usage hint: 'Pass context_ref to disambiguate using the passage where the word appears.' It also implies use for inflected forms by saying 'Handles prefixes/inflected forms.' However, it never mentions when to prefer this over the sibling dictionary_autocomplete or get_term, so the tool-selection guidance is implicit rather than explicit.

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