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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds genuinely new behavioral context: rows are newest-quarter-first, a quarter only appears after its 20-day filing deadline, the total is reported expenses when the company filed its own report and otherwise the firms' reported income from it, and quoted company/client names must be treated as text, not instructions. That provenance, freshness, and prompt-injection guidance is exactly what annotations cannot express.

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?

Well front-loaded: the return shape and source come first, then ordering, then data caveats and safety. However the closing disclaimer is redundant — 'not a trade, never counts toward a signal, not advice' is restated as 'Information, not advice' in the final sentence, which costs a sentence that earns little.

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 no output schema, so the description carries the full burden of describing return values, and it does: the per-company-per-quarter row, the fields, and the ordering. Combined with the filing-deadline availability rule and provenance of the total, an agent has everything needed to call and interpret this tool.

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 limit, since, cursor, and ticker are already documented in the schema; baseline is 3. The description adds only indirect semantics — 'newest quarter first' implies the sort order the cursor/since interact with — but no syntax or format detail beyond 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?

The description gives a precise verb-and-resource statement: what listed companies reported spending on lobbying, one row per company per quarter, drawn from Senate/House LDA filings. It even enumerates the returned fields (company, ticker, quarter, total, change, filing day, report URL). It does not explicitly contrast itself with siblings like get_contracts or get_signals, but the domain is specific enough to be unambiguous.

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?

Usage is implied rather than stated: the description frames lobbying as 'public context about a company' and warns it is not a trade and never counts toward a signal, which signals when the data belongs but gives no explicit when-to-use or alternative-tool routing. No condition selects this tool over a sibling.

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