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

The annotations (readOnlyHint=false, idempotentHint=true, destructiveHint=false) describe the safety profile, and the description adds real context beyond them: the reading is persisted to the account, a new one takes about a minute, and a "writing" status means it should be polled later. It doesn't enumerate other possible statuses or what happens on repeat calls with a differing person object, which keeps it short of a 5.

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?

Front-loads what the tool produces, then the input alternatives, then the async follow-up — a sensible order with no filler. The closing sentence ("Reading text is content for the person") is slightly oblique but roughly earns its place by hinting at the return payload.

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?

There is an output schema, so return values need not be spelled out, and the description still covers persistence, latency, and the polling path an agent must take. For a tool with a nested object parameter, it is complete enough to call correctly on the first try.

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 every field including the nested birth details is already documented, making 3 the baseline. The description reinforces the person-vs-chartId split but says nothing about the `relationship` enum, so it adds only marginal meaning over the schema.

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: writes or returns an already-written personal birth chart reading saved to the Celestio account. It also distinguishes itself from siblings by naming the two input modes (person details vs. chartId) and by pointing at get_reading for the polling case, so an agent can separate it from compute_birth_chart without opening any schema.

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?

Explicitly says to pass either `person` (birth details) or a `chartId` from an earlier result, and gives a concrete next step when status is "writing": call get_reading with readingId shortly. That is clear routing, though it doesn't say when to prefer compute_birth_chart or list_my_readings over this tool.

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