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

Annotations already declare readOnly, idempotent, non-destructive and non-open-world, so the safety profile is covered. The description adds genuinely new context by disclosing the data provenance (AI-extracted from filings) and the comparison mechanism (deltas across consecutive extractions), which affects how the agent should interpret results.

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 tight sentences that front-load the core purpose before elaborating on the compared fields and mechanism. Minor redundancy between 'recent material changes' and 'recent filings', but no wasted 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 values need no prose, and annotations carry the safety profile. Given a two-parameter, read-only tool, the description covers source, scope and mechanism adequately; only the when-to-use routing is missing.

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% for both parameters, so the schema already documents 'days' (default 30, max 365) and 'ticker' (NZX symbol). The description adds no syntax, format or constraint detail beyond what the schema provides, so the baseline 3 applies.

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 ('Get recent material changes for a company') and pinpoints the domain: revenue, profit, dividend and guidance deltas from AI-extracted announcement data. The 'compares consecutive announcement extractions' framing differentiates it from static siblings like get_financials or get_dividends, though it does not name any sibling explicitly.

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 implies a 'recent changes' use case but never says when to choose this over get_announcement_alerts, get_earnings_surprise, get_dividends or get_financials, and gives no exclusions or prerequisites. An agent must infer the routing decision entirely.

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