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

Annotations only cover the safety profile (readOnlyHint, openWorldHint), and the description adds substantial behavioral detail beyond them: default returns the most-filled fields, 'fields_selection' reports how many were omitted, 'a field not shown is not thereby absent', and relationships are declared by the data model and never inferred. The last two points are exactly the kind of non-obvious caveats that prevent an agent from drawing wrong conclusions.

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?

Front-loaded with the core purpose, then the pagination caveat, then the field-name/join guarantees. Every sentence carries distinct information and nothing is repeated from the schema or annotations.

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?

With six parameters, no output schema, and a read-only annotation set, the description compensates fully by describing the returned shape (field list plus fields_selection count) and the relationship semantics. An agent has everything needed to call this correctly and interpret the result.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning: it explains that the default subset is 'most-filled', that matching searches name or description, and that offset pages against the reported total. That clarifies the intent of fields/limit/offset beyond their terse schema strings.

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?

States a specific verb and resource ('Show an entity's selectable fields and its declared relationships to other entities'), which cleanly separates it from list_entities (enumeration) and query (retrieval). The mention of both fields and relationships captures the tool's dual output, so an agent knows exactly what it gets.

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?

Gives concrete routing advice for the optional parameters ('use matching to search by name, fields to name the ones you want, or offset to page') and ties itself to query by noting these are the field names query accepts. It stops short of explicitly naming when NOT to use it versus siblings like list_entities or sample_values, so it is strong context without full exclusion guidance.

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