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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds genuinely new behavioral facts: the CSV column shape (date,type,description,pdf_url) and the fallback to JSON candidate lists on ambiguous input. It does not mention pagination or result caps, but that is a minor gap.

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?

Three sentences, front-loaded with purpose, then the exclusion/alternative, then the return shape. Every clause carries routing or format information; no filler.

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?

No output schema exists, and the description compensates by naming the return format and its columns plus the ambiguity fallback. Combined with fully documented parameters and safety annotations, an agent has everything needed to call this correctly.

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% and the schema already documents symbol typo tolerance, the candidate fallback, and the from/to defaulting rules. The description's mention of 'for a symbol' and the ambiguity behavior largely restates the schema, so the baseline 3 is correct.

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+resource ('Get general CSE company disclosures for a symbol') and enumerates the covered disclosure types (board changes, AGM/EGM notices, listings, suspensions, name changes). It also names the sibling it is not (get_corporate_actions), so an agent can discriminate without opening either 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 routes dividends, rights issues, and share splits to get_corporate_actions and gives the reason (parsed structured detail vs raw text). It also tells the agent what to do when the symbol is ambiguous: surface candidates, ask the user, re-call.

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