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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds substantive context on top: timezone resolution rules, the two-hour/issuing-environment validity of chartContext, the fact that an absent editorial message is a valid result, and caveats about birth-time uncertainty and that contacts do not establish feelings or future events.

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?

Four sentences, front-loaded with the core action, then entitlement, empty-result, and caveat details. Slightly dense with domain jargon ('editorial catalog', 'chart contacts') but no filler sentences.

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?

Covers what an agent needs: output meaning, timezone resolution, entitlement limits, and valid-empty-result semantics, with an output schema handling return values. The disclaimers about birth-time uncertainty and non-predictive contacts fill the remaining gaps.

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%, so both parameters are well documented in the schema itself. The description still adds value by explaining how the timezone default resolves (confirmed viewing/account timezone) and the either/or selection logic between temporary and saved charts.

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 and resource: returns today's personal chart contacts plus a deterministic reflection drawn from the Novamris Today editorial catalog. It is clearly distinguishable from siblings like get_timing_month, compare_dates, and calculate_chart, which operate on other time spans or computations.

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 establishes the usage context: it works with either the temporary chartContext or the authorized saved self chart, and explicitly does not require a full_timing entitlement. It does not name alternative tools for non-today queries, so routing guidance is implied rather than explicit.

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