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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the description's real contribution is the blunt data-completeness caveat: only Sun has full data, the other 8 planets return placeholder text, and the 144-cell database is deferred to Phase 3. It also surfaces cost (20 credits, Tier 2) and the endpoint. Telling an agent the tool is partially stubbed is exactly the kind of context structured fields cannot carry.

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-loaded with the one-line purpose, then the input encoding, then the completeness caveat, with bracketed metadata block for group/endpoint/required/cost. Every sentence carries information; nothing is padding.

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?

An output schema exists, so return-value shape need not be explained. Combined with annotations covering the safety profile and the description covering the critical input encoding and the stub-data limitation, an agent has what it needs to call the tool correctly. Only the missing usage framing keeps it below 5.

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 50%, and the two undescribed parameters are the required ones. The description compensates by giving the planet encoding (0..6, 11=Rahu, 100=Ketu) and the house range (1..12), which the schema's generic safe-integer bounds do not convey at all. It adds nothing for the already-documented `fields` and `precision`, so not a full 5.

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 names a specific resource and action: a short summary of a (planet, house) placement per Lal Kitab. That cell-level scope is inherently distinct from the broader Lal Kitab siblings (lal_kitab_full, lal_kitab_lal_kundali, lal_kitab_teva), so an agent can tell them apart without opening a 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?

The description explains the inputs but gives no when-to-use guidance, no exclusions, and never routes the agent toward or away from the other Lal Kitab tools. Usage is only weakly implied by the tool name and title, so this is a clear gap rather than merely a missing exclusion.

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