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

Annotations only declare flags (readOnlyHint=false, destructiveHint=true, openWorldHint=true, idempotentHint=false); the description adds genuinely useful context the annotations cannot: the return is a private review link rather than a public one, chart annotations are included, and the agent has no publish authority. It doesn't explain what state the destructive-hinted write actually creates or affects, so not a 5.

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?

Five short sentences, front-loaded with the action and its private nature, then the usage gate, then the constraints. Every sentence carries load-bearing information about scope, workflow, or safety; no filler.

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?

No output schema exists, so the description correctly carries the return-value burden ('Returns a private review link, NOT a public link'). Combined with the human-approval workflow and privacy constraints, an agent has enough to call it correctly, though the enum/optional parameters (market, exchange, timeframe, symbol) get no mention.

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 78%, so most of the 9 parameters are already documented in the schema (body, title, caption, levels, indicators all have descriptions). The description adds only thematic constraint ('Do not include private account information') rather than field-level 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 composite resource: 'Prepare a PRIVATE sharing package of the current chart image, editable analysis and social caption.' This clearly distinguishes it from siblings like chart_image, chart_link, or alert_link, which produce images or links without the review/publish workflow.

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?

Explicitly scopes usage with 'Only use when asked for something shareable,' and describes the follow-on flow (the person must open, edit/review, and publish) plus the exclusion 'you cannot publish or post on their behalf.' It doesn't name a specific sibling alternative for the non-sharing case, so it stops short of a 5.

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