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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds meaningful context beyond them: that the operation requires no signature and that results are caller-dependent, which helps an agent reason about output variability.

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 tightly worded sentences with the core action front-loaded and no filler. The trailing caller clarification is brief and earns its place, though the semicolon-delimited notes are slightly terse.

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 single-parameter read tool with no output schema and full annotation coverage, the description supplies what is needed: the resource, the read-only/signing posture, and the caller semantics. It could note the return shape (e.g. two lists), but not required given the absence of an output schema.

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 the schema already documents the single caller parameter (SS58 address to run the query as). The description's note that caller is for 'caller-dependent results' adds a small amount of meaning but largely restates the schema, so baseline 3 applies.

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 (List) and resource (accounts the caller has allowed and blocked for private messaging), which clearly reads as the retrieval counterpart to allow/block sibling tools. It does not explicitly name the mutation siblings, so an agent must infer the distinction, keeping it just below a 5.

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?

Provides contextual facts (read-only, no signature needed, caller is optional) but never states when to use this tool versus alternatives such as get_account_settings_data or the allow/block mutations. Usage is implied rather than guided.

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