brain_get_pref

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

With no annotations provided, the description carries the full burden. It discloses the read-only nature implicitly ('Read back'), explains the two invocation modes, and reveals that a default note is returned for missing keys. It does not explicitly state that it has no side effects, requires no special permissions, or any performance characteristics, but it is adequate for a simple getter.

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?

Three sentences, zero wasted words. The first sentence states the core purpose, the second explains the two modes of usage, and the third adds the default note behavior and the complement tool. Front-loaded and efficient.

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?

The tool is simple with 2 parameters and no output schema. The description covers purpose, invocation modes, and the missing-key behavior. It mentions the complement tool. The only minor gap is that it does not describe the return format (e.g., JSON object with key-value pairs), which would be helpful for an agent. Overall, it is nearly 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 100% with parameter descriptions already present. The description adds value by explaining the behavior of omitting the key (list all preferences) and the return behavior for missing keys ('Returns a default note'). This goes beyond the schema's minimal description.

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 clearly states the verb 'Read back' and the resource 'preferences stored for this Brain instance'. It distinguishes two modes (single key vs. all) and explicitly names the sibling tool 'brain_set_pref' as complement, making differentiation from the 100+ sibling tools easy.

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 explicitly tells when to use a key (get a single value) and when to omit it (list all preferences). It also mentions the complement 'brain_set_pref', implying the write counterpart. However, it does not explicitly state when NOT to use this tool or provide exclusions for other read alternatives.

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