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

With no annotations provided, the description carries the full transparency burden. It does well by disclosing the return shape ('Each period carries lord, ISO start/end, duration in years, and whether it is the one currently running') and the hierarchical traversal semantics, including a chara_jaimini quirk. It doesn't mention auth, rate limits, or explicit read-only status, but the operation is clearly a non-mutating list.

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?

The definition is well organized and front-loaded with purpose and usage, then a clear Args block. It is slightly longer than strictly necessary because the usage examples in the second paragraph partially repeat what the within parameter documentation later conveys, but every section still adds distinct value and nothing is wasted.

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 3-parameter tool with no output schema, the description is fully complete: it covers all supported systems, defaults, the drill-down behavior, the special chara_jaimini case, and the exact fields carried by each period. An agent has everything needed to format a correct call and understand the result structure.

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 0%, so the description compensates exceptionally. It explains chart_id as a handle returned by create_chart, enumerates all valid system values with their default, and fully explains the within hierarchy with concrete examples for None, ['Sun'], and ['Sun', 'Mercury'], plus the special chara_jaimini rashi-keyed caveat. This is far more valuable than the raw schema alone.

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 opens with a specific verb and resource: 'Walk the dasha tree — list periods at any level, past or future.' It clearly distinguishes itself from get_current_dasha by explaining that the sibling only tells you what is running now while this tool gives the whole sequence. This fully separates it from siblings in a single glance.

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 gives concrete user questions: 'when does my next antardasha start', 'what runs after this mahadasha', 'when was I in Jupiter'. It explicitly names the alternative get_current_dasha and explains the boundary between the two tools, which is exactly the when-to-use vs when-not-to-use guidance an agent needs.

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