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

Annotations declare readOnly/idempotent/destructive hints. Description adds valuable behavioral context not in annotations: cost ('Free'), return structure ('array of candidate objects'), and downstream consumption pattern. No contradictions with annotations.

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?

Five sentences, each serving distinct purposes: action definition, return structure, workflow integration, prerequisites, and cost. Information is front-loaded with the primary verb and contains zero redundancy.

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?

Given low complexity (1 parameter, 100% schema coverage) but absence of output schema, description fully compensates by detailing the return structure ('array...with id field') and workflow relationships. No gaps remain for agent invocation.

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?

With 100% schema coverage (baseline 3), description adds semantic value by specifying the data lineage for context_id ('from atlas_create_context or atlas_list_contexts'), guiding the agent on how to source the parameter value.

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?

Description uses specific verb 'List' with resource 'candidates' and scope 'in a hiring context'. It distinguishes from sibling 'atlas_get_candidate' by emphasizing 'all' and 'array' return type, while clarifying the specific hiring domain context.

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 explicit prerequisite ('Requires context_id from...') and workflow integration ('Use candidate id as candidate_id in...'), establishing clear context for when to use the tool. Lacks explicit 'when-not-to-use' guidance or direct alternative comparison (e.g., vs. atlas_get_candidate), preventing a 5.

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