kb_at

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

Explicitly documents that missing keys return {error: not_found} and indicates side-effect-free access with 'Read-only;' – behavior that's aligned with annotations and covers the key error case. The description doesn't cover what happens on success beyond returning it, but for a read-only fetch this is sufficient. One of the better aspects of the documentation.

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 tightly pack purpose, error semantics, and side-effect behavior without excess. The inscription 'hard-link' and 'shared document store' adds some color, but may be overly compressed, making it slightly opaque for a new reader.

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 two-parameter read-only accessor without output schema, it covers the key scenarios: the index (exact ID), the miss case ({error: not_found}), and the absence of side effects. Misses the response shape, but that's acceptable for a read-only read of a simple interface, and the description handles all core aspects adequately.

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%, so the description bears full responsibility for explaining the parameters, but it completely fails to distinguish app_id from atom_id, nor does it explain which is the 'exact' ID. The phrase 'by its exact ID' is singular, but there are two required parameters, leaving the reader to guess that atom_id is the identifier and app_id is a namespace (or similar distinction), which is the primary weakness of this documentation. The description adds essentially no value over the parameter names themselves.

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?

Clear verb+object: 'Fetches a knowledge-base entry by its exact ID from the shared document store' – a direct accessor that is clearly distinct from the fuzzy search alternative. However, the exact composition of the key (app_id vs atom_id) is ambiguous, and the phrase 'hard-link to knowledge_base' is cryptic, making the core purpose slightly fuzzy around the edges.

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?

'By its exact ID' implies a when-to-use scenario (you know the ID, use this), and the mention of a 'hard-link to knowledge_base' gestures at an alternative, but it's not explicit. The description fails to truly contrast with knowledge_search and leaves the choice to inference, but doesn't leave it entirely to chance.

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