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

The annotations already declare that this is a safe, closed read operation, and the description adds genuinely useful behavioral context: results start with the newest record, symbols return mentions and tone while repos return stars, and the tool requires a Pro tier. Only pagination behavior at the large limit ceiling goes unaddressed.

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 description is one sentence with no filler, and the key facts appear up front: the resource, the supported kinds, the ordering, and the plan requirement.

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?

With four parameters, an annotation set that already covers the safety profile, and no output schema, the definition is adequate but incomplete: it never says how far back history goes or what the limit means in practice, so an agent cannot reason about the scope of the returned series.

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 sits at 75%, and the schema itself already defines the key format (tag, BTC, owner/name) and the resolution values. The description reinforces the mapping between kind and key type in prose, but it says nothing about what the limit actually does or how it interacts with the newest-first ordering.

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 states a specific verb and resource combination ('Stored hourly or daily history') and enumerates the three key types it supports: hashtag, symbol, and GitHub repo. It is clear enough to distinguish this tool from live or aggregate siblings such as social_network_stats or social_symbol_mentions, though it does not name an alternative 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?

It touches usage only indirectly. The word 'Stored' suggests this tool returns historical series rather than current values, and the '(Pro)' note hints at a plan requirement. It never says when to choose this tool over a sibling or what distinguishes it from a stats tool, so any guidance must be inferred.

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