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

Goes well beyond the read-only/idempotent annotations by disclosing plan-gated behavior (free plans return `redacted: true` with no member attribution) and a real interpretive trap: most decisions are unanimous voice votes with `roll_call: false` and no tally, yet must still be reported. This is exactly the kind of behavioral context an agent cannot derive from annotations or schema.

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?

Purpose is front-loaded, followed by WHEN / WHEN NOT and a single concrete example, with zero filler. Every sentence carries a distinct load: scope, plan behavior, edge case, routing, and a usable call snippet.

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 three-parameter, output-schema-backed read tool, the description covers everything an agent needs: scope, selection criteria, sibling routing, plan gating, and a data-interpretation warning. Return values are already covered by the output schema, so nothing material 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 coverage is 100%, so city, since, and limit are already fully documented in the schema; the description adds no syntax, format, or edge-case meaning for them. The worked example demonstrates a valid call but does not extend parameter semantics, 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 — the 'changeset of council activity in a city since a date' — and enumerates exactly what it contains (decisions with tallies, issues discussed, development-application status changes, paid-plan member votes). It further distinguishes itself from siblings by naming track_position and issue_timeline as the wrong tools for single-entity queries.

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?

Explicit WHEN section gives sample user questions ('What did the council do in the last two weeks?') and an explicit WHEN NOT that routes single-person or single-issue longitudinal queries to track_position / issue_timeline. The alternative and the condition selecting it are both stated.

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