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

With destructiveHint=true already declared, the description still adds substantial context the annotations do not carry: hard limits (50 columns, 1,000 data rows, 1,000 characters per cell, 24,000 bytes), the special rule that an oversized stored sheet may be resubmitted or shrunk but is rejected if it grows, and the requirement to sign an "update" action over sheetMarkdown output. That is exactly the operational behavior an agent needs before a destructive overwrite.

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, each carrying distinct information: identity/scope, limits and rejection behavior, then the signing contract. Limits are front-loaded right after the verb, and there is no filler or restatement of the title.

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 an 11-parameter, 9-required destructive write with no output schema and no schema descriptions, the definition covers limits and signing but leaves critical gaps: the role of baseRevisionId in conflict handling, the meaning of kind, and the optional message. It is enough to call the tool, but not enough to call it correctly under concurrency.

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 0%, so the description must compensate, and it partly does: it explains how columns/rows flow through sheetMarkdown({name, columns, rows}) and what the signing inputs are expected to cover. It never mentions baseRevisionId (the optimistic-concurrency check), the message field, or the human/agent kind enum, so several of the 11 parameters remain unexplained in both schema and description.

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 opening "Replace your own spreadsheet" gives a specific verb (replace) and resource (spreadsheet), and "your own" scopes it to the caller's document, which separates it from the sibling create_spreadsheet. It stops short of naming a sibling such as edit_markdown or suggest_edit to sharpen the boundary, but an agent can still identify the operation immediately.

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 word "Replace" implies a full overwrite rather than a partial patch, which is meaningful usage guidance, and the sentence about larger stored sheets being resubmitted/shrunk tells the agent how a specific case behaves. However, there is no explicit when-to-use/when-not guidance and no named alternative for the partial-edit or suggested-contribution paths, leaving the agent to infer the boundary with suggest_edit.

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