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

With no annotations, the description carries the full disclosure burden: 'Read' establishes a non-mutating operation and 'built from its Entity Document' signals the card is derived rather than stored. It does not cover failure behavior when no Entity Document exists, permission requirements, or any note that the url parameter becomes mandatory outside extension-only mode.

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?

One compact sentence with the primary purpose front-loaded and the optional mode parenthetically scoped; no filler or restatement of the title.

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 three-parameter, no-output-schema, no-annotation tool, the description covers the core operation but leaves the entity identifier semantics, the url requirement rationale, and error/empty cases unexplained. Adequate to attempt a call, but not complete.

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 only 33% — 'url' is documented in the schema while 'eid' and 'extension_only' are not. The description partly compensates by explaining that the extension-only variant returns just the AgentExtension block, but it adds nothing about the eid format or why url is required in the default mode.

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 ('Read') and resource ('entity's A2A Agent Card / Open Entity AgentExtension block') and notes it is derived from the Entity Document. It does not, however, differentiate itself from close siblings like openentity_read, openentity_present, or openentity_resolve, so an agent must guess which read-shaped tool fits.

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 says what the tool returns but never says when to choose it over openentity_read, openentity_present, or openentity_find. The parenthetical about the extension block hints at a mode rather than articulating usage conditions or exclusions.

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