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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered by structured data; the description still adds real value beyond that: an unknown UUID returns a not-found error, names are not accepted as input, and the record deliberately excludes relations, neighbors and episodes. Minor redundancy in restating 'Read-only' costs it the top mark, but the error behavior and scope boundaries are genuinely useful disclosures.

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 action and return payload, then usage, then alternatives, then the single argument. Every sentence carries a distinct fact; the Args block is not padding because the schema provides no parameter description at all.

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?

There is no output schema, but the description compensates by enumerating the returned fields, and it covers the error path (not-found) and the scope boundaries. For a single-parameter read tool, an agent has everything needed to call it 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 0% -- the schema only says 'Entity Id' as a bare string -- so the description carries the full burden, and it does: it specifies the format (UUID), points to a concrete source ('the `id` returned by search_entities'), and adds a negative constraint ('Names are not accepted') that prevents a common misfire. This is exactly the compensation a low-coverage schema needs.

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 -- 'Read one entity's own record by UUID' -- and immediately enumerates what is returned (type, attributes, aliases, version, epistemic status, timestamps). The 'own record' phrasing and the explicit exclusion of relations/neighbors/episodes distinguish it cleanly from get_entity_graph_context, get_entity_relations and get_entity_episodes in the sibling list.

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 the exact precondition ('when you already hold an entity UUID'), names where such a UUID comes from (search_entities, a relation, an episode), and routes to three named alternatives for the cases this tool does not cover. It also states that search_entities is the tool for resolving a name to a UUID, closing the obvious loop.

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