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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds useful context that authentication via X-License-Key is required and that the namespace is persistent, but it does not detail failure behavior, rate limits, or other operational constraints.

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 three short sentences with zero waste, and it front-loads the primary retrieval purpose before adding safety and authentication context.

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?

An output schema exists, annotations cover read-only behavior, and the input schema documents both parameters. The description is complete enough for an agent to invoke the tool correctly, though it could mention how missing keys are handled.

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 100%, so both 'key' and 'space_id' are already documented in the input schema. The description adds little parameter-level meaning beyond naming the object being retrieved, which is appropriate given the schema's 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 states a specific verb, 'Retrieves', and a clear resource: a named typed variable, AST, symbol table, or state object from the V_t swarm namespace. It distinguishes the operation from mutation siblings like icx_var_set, though it does not explicitly name alternatives.

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 implies usage by saying it retrieves a named variable from the persistent namespace, and notes it is read-only with license-key authentication. However, it does not explicitly say when to use this instead of icx_var_list, icx_recall_scoped, or other retrieval siblings.

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